Tag: Nutrients

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The Web Beneath the Roots — What Actually Happens in Living Soil

ow a mycorrhizal fungus reshapes the bacteria living around a root — and what that means for cannabis living soil.
The Web Beneath the Roots — Going Deeper Into Living Soil | The Certified
The Grower's Connect
Soil Biology · Living Soil

We introduced the soil food web a while back — bacteria, archaea, fungi, protists, nematodes, all of it. Last week we went underground again, straight into the root itself, and found real medicine hiding there. This week we zoom back out one level, to the ground the root actually lives in, and look at a study that captures something living soil growers talk about constantly but rarely see measured: a mycorrhizal fungus walks into a root zone, and the bacterial neighborhood changes because of it.

Soil Biology · Mycorrhizal Fungi · Rhizosphere Ecology

The Web Beneath the Roots — What Actually Happens in Living Soil

"Feed the soil, not the plant" is the mantra. But what does that actually look like at the microbial level? A 1984 grassland study tracked exactly what happens to the bacteria living around a root once a mycorrhizal fungus moves in — and the answer is more interesting, and more specific, than "everything grows more."

The Grower's Connect · · 13 min read
5 groups bacteria, archaea, fungi, protists, and nematodes make up the core cast of the soil food web
5.5% maximum root length the mycorrhizal fungus colonized — still enough to shift the bacteria around it
3 of 5 comparison methods where mycorrhizal colonization significantly boosted one specific rhizosphere bacterium
r = 0.53 correlation between mycorrhizal colonization and that bacterium's population, P = 0.01
Listen to this article The Web Beneath the Roots
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Every grower who's committed to living soil already believes something like this: the soil isn't an inert bag of nutrients, it's a community, and the health of your plant depends on the health of that community. It's a good instinct, and it's the whole premise of this series. But "community" is a word that can quietly do a lot of hand-waving. It's easy to nod along with "feed the soil, not the plant" without ever seeing what that community is actually doing to itself, in real numbers, while your roots sit in the middle of it.

That's what makes an old, unglamorous study out of Colorado State University worth pulling back out. It isn't about cannabis, and it isn't recent — it was published in 1984, in a grassland soil, on a grass species most growers have never heard of. But it did something most soil-biology writing doesn't: it isolated one single relationship inside the soil food web — a mycorrhizal fungus and the bacteria living in its immediate neighborhood — and simply measured what happened. No hand-waving. Counted colonies, on plates, compared with statistics. That kind of unglamorous, methodical measurement is exactly what makes the more general "soil food web" story feel less like philosophy and more like biology you can build a growing method around.

A Quick Refresher: Who's Actually Down There

Before going deeper, it's worth restating the cast, because the rest of this piece leans on all of them. The soil food web is built on primary decomposers — bacteria and archaea — that break down organic material and release the nutrients locked inside it. Bacteria in particular drive nitrogen fixation, most famously through the Rhizobia species that trade fixed nitrogen for sugar inside legume root nodules, and they compete aggressively with pathogens for the same space and food. Fungi split into two working groups: mycorrhizal fungi, which form direct symbiotic partnerships with roots and extend a plant's effective reach for water and phosphorus far beyond what the root itself could access, and saprophytic fungi, which decompose dead organic matter and physically bind soil particles together with their mycelium. Above them, protists graze on bacteria and release the nitrogen they contain as plant-available ammonium, while nematodes feed on bacteria, fungi, other nematodes, or roots depending on the species, and in doing so regulate the size of every population beneath them.

On paper, this reads like a food chain. In practice, it behaves more like an economy — thousands of overlapping transactions happening in the thin films of water around every soil particle, all of it ultimately funded by whatever the plant's roots are putting into the ground. And that's the part this week's study actually gets inside of.

The Study: What Happens When a Fungus Moves Into the Root Zone

Researchers R. N. Ames, C. P. P. Reid, and E. R. Ingham — yes, that Ingham, the same microbiologist whose work popularized the term "soil food web" in the first place — grew blue grama grass in sandy, nutrient-poor soil collected from a Colorado grassland. Half the plants were inoculated with Glomus mosseae, a vesicular-arbuscular mycorrhizal (VAM) fungus, at transplant. The other half were grown exactly the same way, without the fungus. Both groups had the same five species of naturally occurring rhizosphere bacteria inoculated into their soil from the start, so every plant began with an identical microbial starting lineup.

Sixty days later, the researchers harvested everything and counted. They measured bacterial populations in the soil that fell away from the roots easily — the "non-rhizosphere" soil — and separately in the soil that clung tightly to the root surface, the true rhizosphere zone. They also measured how much of each root system the mycorrhizal fungus had actually colonized, and cross-checked all of it against root length, root branching, and shoot growth.

Non-Rhizosphere Soil

Soil that fell away from the root easily during handling — the general soil body, still influenced by the plant but not in direct root contact.

Rhizosphere Soil

Soil still clinging to the root surface after gentle shaking — the immediate zone shaped directly by root exudates and root-surface chemistry.

The distinction matters more than it sounds like it should. The rhizosphere is a genuinely different biological neighborhood from the soil a few millimetres further out — a definite zone, as the researchers put it, existing as little as two to four millimetres from the root surface. If a mycorrhizal fungus changes anything about bacterial life, this is where you'd expect to see it first.

The Fungus Barely Colonized the Root — And Still Changed the Neighborhood

Here's the detail that should reframe how growers think about mycorrhizal inoculation: colonization of the root system by G. mosseae topped out at only 5.5% of the lateral root length measured. This wasn't a case of the fungus taking over the root system and obviously dominating its biology. It was a light, partial colonization — and it was still enough to produce measurable, statistically significant shifts in the surrounding bacterial community.

Not More Bacteria — Different Bacteria

The most common assumption about "living soil" is that more biological activity is uniformly better — more bacteria, more fungi, more of everything, all the time. This study complicates that picture in a useful way. Regardless of which measurement basis the researchers used, one bacterial species — a fluorescent, oxidase-positive Pseudomonas-type isolate labelled CB11 — increased significantly in the rhizosphere of mycorrhizal plants compared with non-mycorrhizal ones, in three of the five comparison methods tested. Its numbers correlated with how much of the root system was mycorrhizal, and separately with how many mycorrhizal lateral roots existed.

That last point is the one worth sitting with. It isn't just that individual bacterial populations moved up or down. The relationships between different bacteria changed depending on whether a mycorrhizal fungus was present at all. Two species that behaved independently of each other in ordinary soil started behaving as a pair once the fungus arrived. That's not a change in quantity. That's a change in the structure of the community itself — which is precisely the kind of thing the term "soil food web" is trying to describe, and precisely the kind of thing that's nearly impossible to see without an experiment built to isolate it.

"The mycorrhizal fungus didn't just add another organism to the soil. It rewired which bacteria were connected to which — the kind of shift you'd never catch by counting biomass alone."

Root Exudates: The Currency Nobody Sees

The researchers' own explanation for these shifts centers on root exudation — the sugars, amino acids, and other compounds a root leaks into the soil around it, which serve as the primary food source for much of the rhizosphere's bacterial life. The working theory is that mycorrhizal colonization changes what and how much a root exudes, which in turn changes which bacteria can thrive nearby. It's a plausible mechanism, and it lines up with earlier work cited in the paper showing reduced sugar and amino acid content in root exudates from mycorrhizal plants compared with non-mycorrhizal controls of a different species.

But the authors are honest that this raises as much as it resolves. If mycorrhiza formation generally reduces root exudation, why would specific exudate-dependent bacteria like CB11 increase rather than decrease around mycorrhizal roots? Their answer, and ours: the soil food web doesn't run on a single tap that turns uniformly up or down. It's plausible the fungus is changing the exudate mixture rather than simply throttling its volume — favouring compounds that specific bacteria prefer, while starving out others. Nobody has measured that directly yet. It's a genuinely open question, which is a more honest place to land than pretending the mechanism is settled.

Why This Should Matter for Cannabis Growers Specifically

Cannabis forms its own arbuscular mycorrhizal relationships, and living-soil cultivation leans on that fact constantly — mycorrhizal inoculants are a staple ingredient in most living soil mixes and no-till beds. What this study adds isn't a claim about cannabis directly; blue grama grass and sandy Colorado rangeland soil are a long way from a cannabis root ball in a fabric pot. What it adds is a concrete, measured example of the mechanism living soil growers are actually relying on when they inoculate with mycorrhizal fungi at all: the fungus isn't just a nutrient-delivery shortcut for the plant. It's an organism that reaches into the surrounding bacterial community and reorganizes it — promoting some populations, suppressing others, and creating new relationships between bacterial species that didn't exist before it arrived.

The Honest Limitations

This is a forty-year-old study on a wild grass species, grown in a greenhouse pot for sixty days, in sandy Colorado rangeland soil with very low native nutrient levels. None of that is cannabis, none of it is a living soil bed, and none of it is a full growing season. The correlations reported — including the r = 0.53 relationship between CB11 and mycorrhizal colonization — are correlations, not proof that the fungus directly caused the bacterial shift; the researchers themselves note that the mechanism connecting the two remains genuinely unclear. Counts of one inoculated bacterial species, an Azotobacter, couldn't be reliably measured at all and were dropped from the analysis. And critically, results changed depending on how the data were expressed — per gram of rhizosphere soil, per gram of whole root, per gram of lateral root, per centimetre of lateral root, or per number of root branches all told a slightly different statistical story, which the authors themselves flag as a problem still unresolved in this field: there's no agreed-upon standard for how to measure a rhizosphere population in the first place.

None of that erases the value of what was shown. This remains one of the few studies that isolated a single mycorrhizal fungus-bacteria interaction cleanly enough to put numbers on it, rather than just observing that "biology was different" between treatments. For a series that keeps circling back to the same idea — that soil is a web of relationships, not a stack of independent ingredients — this is what that idea looks like in raw data, decades before "living soil" was a marketing term.

Mycorrhizal fungus and rhizosphere bacteria interaction: Ames, R. N.; Reid, C. P. P.; Ingham, E. R. Rhizosphere Bacterial Population Responses to Root Colonization by a Vesicular-Arbuscular Mycorrhizal Fungus. New Phytologist 1984, 96, 555–563. Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado.
Foundational soil food web framing: Concept popularised by Dr Elaine Ingham and drawn from Jeff Lowenfels' Teaming with Microbes, as introduced in our earlier post, "What is the Soil Food Web?"
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The Compost Clock

The Compost Clock
The Compost Clock — Manure Timing & Blends for Cannabis | The Certified
The Grower's Connect
Cultivation Science · Composting

Continuing our cultivation science arc — last week we looked at how cover cropping versus tillage reshapes cannabinoid and terpene profiles. This week we go one layer deeper: what's actually going into that soil, and how long it needs before it's ready. We're bringing together three separate studies — on compost maturation timing, combined organic-and-inorganic fertilization in hemp, and manure's effect on heavy metal mobility — and reporting back where they agree.

Cultivation Science · Soil Health · Composting · Research

The Compost Clock — What the Data Actually Says

Growers love mixing raw manures and stretching synthetic fertiliser with organic inputs. Three studies — on compost timing, combined organic-inorganic feeding, and manure-driven heavy metal mobility — show it can genuinely work. But maturity isn't optional, ratio isn't cosmetic, and manure source carries real consequences.

The Grower's Connect · · 14 min read
30 days to full compost maturity under the best-performing manure ratio
101% vs 61% germination index at day 30 — best manure ratio vs the one that failed to mature
≈0% growth gain from raw, uncomposted digestate vs a properly composted blend
+170% cannabinoid yield from the best organic-plus-reduced-mineral blends
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Ask ten growers what "the compost is ready" means and you'll get ten different answers. Some go by smell. Some go by colour. Some go by a date circled on a calendar three or four weeks after the pile went down. Almost none of them are testing for it directly, and almost none of them are thinking carefully about what manure they used to build the pile in the first place.

That gap — between compost-by-feel and compost-by-data — is where this week's reading sits. We pulled together three studies that, between them, cover the whole chain a grower actually cares about: how long composted manure takes to stop being immature and start being safe, what happens to plant growth and cannabinoid chemistry when you combine organic inputs with a reduced rate of synthetic fertiliser, and — the part almost nobody talks about — what manure application does to heavy metal mobility in soil, given that cannabis itself is an unusually efficient metal accumulator. None of the three studies used identical crops or conditions, so we're not stitching them into one seamless story. But where they line up, the agreement is worth taking seriously, and where they diverge, that's useful information too.

How Long Does Compost Actually Take?

A 2023 study out of Anhui University of Science and Technology in China set out to answer this with real numbers. Researchers composted wheat straw with pig manure or cow manure at 20%, 30%, and 40% ratios, plus a microbial inoculant, and tracked the pile daily for thirty days — temperature, pH, electrical conductivity, nitrogen forms, and a seed germination index, the standard lab proxy for whether a compost is mature enough to stop harming plants.

Under the best-performing ratio in this study — 40% cow manure to 60% wheat straw — the germination index reached 101% by day thirty, comfortably past the "fully mature" threshold. That treatment also showed the fastest organic matter breakdown and the best nitrogen and phosphorus retention of any group tested. Thirty days, with turning every two to three days, was enough to get there.

"The calendar date isn't the test. The germination index is the test — and one manure ratio in this study never crossed the finish line by day thirty."

Manure Ratio Matters More Than Manure Amount

Here's the part growers mixing raw manures need to sit with: not all manure-to-straw ratios matured at the same rate, and more manure was not automatically better. The treatment using 40% pig manure was the standout underperformer across the board.

Cow Manure — Scales Well

Organic matter degradation rate and nitrogen/phosphorus retention both improved as the cow manure ratio increased, peaking at 40%. The 30% and 40% cow manure treatments were the two best performers overall on the study's combined maturity score.

Pig Manure — Doesn't

At 40% pig manure, the pile's germination index actually fell below its pre-composting starting point, ending at 61% by day thirty — the only treatment that failed to reach full maturity. The researchers concluded excess pig manure actively inhibited pile decomposition rather than accelerating it.

The overall ranking, using the study's combined "how decomposed is this pile" score across nine indicators: 40% cow manure came out on top, followed by 30% cow manure, then the unamended straw-only control, then the lower pig manure ratios, with 40% pig manure dead last — worse than doing nothing at all. If you're building your own manure blend this spring, that's a concrete, tested reason to lean toward cow manure over pig manure when pushing ratios higher, and to be cautious about assuming "more manure, more nutrients, better compost" holds in a straight line.

What Happens When You Skip the Cure

The composting study above is about wheat straw, not cannabis directly. But a separate 2025 field trial on industrial hemp, run by Italy's Council for Agricultural Research and Economics, gives a striking real-world echo of the same lesson — using an actual hemp crop.

Researchers tested nine fertility treatments on field-grown hemp: no fertiliser, full synthetic NPK, six different composted blends of solid digestate with cardoon waste or spent mushroom substrate, and — critically — the same solid digestate used raw, uncomposted, all paired with half the normal synthetic nitrogen rate. Every composted blend except one modest underperformer produced meaningfully more plant growth and phytochemical accumulation than the unfertilised control. The raw digestate did not.

Put plainly: two organic inputs went into the same field at the same nutrient rate, and only one of them had been given time to mature. The one that hadn't performed almost identically to no fertiliser at all. That's the composting study's warning, showing up independently in an entirely different crop, on an entirely different continent.

The Organic-Plus-Reduced-Synthetic Combo That Actually Worked

The hemp trial's more encouraging finding is the one growers asking about cost-effectiveness will want: replacing half the synthetic nitrogen rate with a well-matured compost did not come at the expense of growth or chemistry — for the right blends, it matched or beat full-rate synthetic fertiliser.

The Heavy Metal Caveat Almost Nobody Talks About

Here's the piece that tends to get skipped when growers discuss manure blends purely in terms of nitrogen, phosphorus, and potassium: manure doesn't only deliver nutrients. If the manure — or the soil it's going into — carries any heavy metal load, cannabis is unusually good at pulling it into a more available, more uptake-ready form.

A 2012 Iranian study tested this directly on a lead- and cadmium-contaminated soil, treating it with cow manure, poultry manure, and their water extracts, then growing cannabis in it for eight weeks. This is a more extreme scenario than most growers will face — the soil was deliberately built from mine-contaminated material — but the directional findings are worth knowing.

What This Means for Your Next Compost Pile

The Honest Limitations

These three studies weren't designed to be read together, so some caution is warranted in how far we stretch the connections. The composting study used wheat straw and never tested cannabis directly — its germination index readings came from cucumber seeds, a standard proxy, not from cannabis itself. The hemp fertilisation trial used composted digestate and cardoon waste, not the manure-and-straw blends from the composting study, so the specific ratios don't transfer directly. And the heavy metal study used a soil deliberately built to be heavily contaminated, cultivated for only eight weeks, in a single Iranian cannabis cultivar under greenhouse conditions — a long way from a typical outdoor grow. What connects them is the underlying pattern, not a single unified dataset: maturity and manure source are not incidental details, they are variables that measurably change what you harvest.

Taken together, these findings support what many growers already suspect from experience — combining organic and reduced-rate synthetic fertilisation is a genuinely viable, evidence-backed approach, not just a workaround. But the studies are equally clear that the benefit depends entirely on getting the input right before it goes in the ground: mature, well-ratioed, and sourced from land you actually trust.

Composting timeline: Fan T, Zhang X, Wan Y, Deng R, Zhu H, Wang X, Wang S, Wang X. Effect of Different Livestock Manure Ratios on the Decomposition Process of Aerobic Composting of Wheat Straw. Agronomy 2023, 13, 2916. doi:10.3390/agronomy13122916 — School of Earth and Environment, Anhui University of Science and Technology, China.
Organic-plus-inorganic hemp fertilisation: Sicignano M, Beleggia R, del Piano L, Enotrio T, Suriano S, Raimo F, Trono D. Effect of Combining Organic and Inorganic Fertilizers on the Growth of Hemp (Cannabis sativa L.) Plants and the Accumulation of Phytochemicals in Their Inflorescence. Plants 2025, 14, 1519. doi:10.3390/plants14101519 — Council for Agricultural Research and Economics (CREA), Italy.
Manure and heavy metal mobility: Safari Singani AA, Ahmadi P. Manure Application and Cannabis Cultivation Influence on Speciation of Lead and Cadmium by Selective Sequential Extraction. Soil and Sediment Contamination: An International Journal 2012, 21(3), 305–321. doi:10.1080/15320383.2012.664186 — Bu-Ali Sina University, Hamedan, Iran.
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Feed the Soil, Shape the Chemistry

Feed the Soil, Shape the Chemistry
Feed the Soil, Shape the Chemistry — What Three Growing Seasons Reveal About Soil and Your Cannabinoid Profile | The Certified
The Grower's Connect
Cultivation Science · Soil Health

Continuing our cultivation science arc — we've covered harvest timing, pathogen damage, and long-term storage. This week we go underground, with new field data on how cover cropping versus tillage reshapes your plant's chemistry before it even flowers. For background, revisit our earlier looks at the soil food web, permaculture principles, and understanding soil.

Cultivation Science · Soil Health · Agronomy · Research

Feed the Soil, Shape the Chemistry

A three-season field trial compared two hemp cultivars grown side by side in cover-cropped, no-till soil and conventionally tilled soil. The totals didn't move much — but the individual cannabinoids and terpenes shifted dramatically, in ways every grower planning August land prep should understand.

The Grower's Connect · · 12 min read
6.4× higher soil aggregate stability under cover cropping — 35.2% vs 5.5%
6× more THC in Tangerine grown on tilled soil vs cover-cropped soil
3.7× more CBG in CBG Stem Cell grown on cover-cropped soil
n.s. difference in total cannabinoid content between fields — profile shifted, not the sum
Listen to this article Feed the Soil, Shape the Chemistry
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Every grower has a theory about soil. Some swear by heavy tillage and a clean seedbed. Others have gone all-in on no-till and cover crops, convinced the extra effort in the off-season pays off in the flower. Until recently, that debate ran almost entirely on intuition and borrowed wisdom from vegetable farming — nobody had actually put two identical hemp cultivars into a cover-cropped field and a conventionally tilled field, grown them side by side for multiple seasons, and measured what came out the other end.

A study published this year in the Journal of Medical Active Plants by researchers at Penn State's Center for Cannabis and Natural Product Pharmaceutics finally did exactly that. Over two full growing seasons, they grew two high-CBG hemp cultivars — Tangerine and CBG Stem Cell — in neighbouring fields on the same farm: one maintained with long-term cover cropping and no tillage, the other conventionally tilled. Same sunlight, same rainfall, same planting density, no added fertiliser to either field. The only deliberate difference was what had been done to the soil.

With August land prep approaching, this is the ideal moment to look closely at what they found — because the results are not the simple "healthier soil, better yields" story you might expect. They're more interesting, and more useful, than that.

What "Soil Health" Actually Measures

Before comparing outcomes, it's worth understanding what separated the two fields in the first place. The researchers used a full Cornell Soil Health Laboratory assessment — the same framework we introduced in our earlier post on understanding soil — scoring each field from 0 to 100 across physical, biological, and chemical indicators.

In other words, this wasn't a marginal comparison. By almost every biological and structural measure, the cover-cropped soil was healthier soil. The open question was whether that translated into a better plant.

The Surprise: Totals Barely Moved

If you were expecting cover-cropped soil to simply produce "more" cannabinoids and terpenes, the headline result will surprise you. Total cannabinoid content — the sum of everything measured — showed no significant difference between the two fields, and no significant difference between cultivars either. Extraction yield and wax content were also statistically indistinguishable between cover-cropped and tilled plants.

"The differences weren't in how much the plant produced. They were in exactly what it chose to produce."

That's the finding worth sitting with. Soil quality, in this study, didn't act like a volume dial for cannabinoid production. It acted like a mixing desk — pushing some compounds up and others down, while the overall output stayed roughly level.

What Actually Shifted — Cannabinoid by Cannabinoid

Once the researchers broke total cannabinoid content down compound by compound, and cultivar by cultivar, the picture changed completely. Significant, sometimes dramatic, differences appeared — and critically, the direction of the shift depended on which cultivar was growing in which soil.

Read that closely and a pattern emerges: soil type didn't have one universal effect. Tangerine and CBG Stem Cell responded to the same two fields in genuinely opposite ways for CBD and CBDA. Any grower hoping for a simple rule — "cover crop for more CBD" or "till for more THC" — needs to reckon with the fact that genetics decided the direction of the response as much as the soil did.

The One Consistent Signal: CBG

Amid all that cultivar-dependent noise, one pattern held steady across both years of the study: cover-cropped soil consistently produced higher levels of CBG, the precursor cannabinoid that plants normally convert rapidly into CBD, THC, and CBC. That consistency — repeated across seasons and lining up with earlier pilot-year data — makes it the most robust finding in the paper.

The Terpene Twist: Soil as a Stabiliser

Terpene content told a different kind of story. Cover-cropped extracts trended higher in total terpenes than tilled extracts (roughly 30 mg/mL versus 21.6 mg/mL), though with considerable variability. The more striking result was in how the two cultivars compared to each other within each field.

Cover-Cropped Field

No significant differences in individual terpene levels between Tangerine and CBG Stem Cell. Two genetically distinct cultivars, grown in the same healthier soil, produced statistically indistinguishable terpene profiles.

Tilled Field

Sharp divergence between the same two cultivars — Tangerine came in significantly lower across several major terpenes, including α-humulene, β-farnesene, β-myrcene, and trans-caryophyllene, compared to CBG Stem Cell in the same field.

The implication is that cover-cropped, biologically active soil may buffer some of the genetic variability between cultivars, producing more uniform terpene expression regardless of which strain you're growing. Tilled soil, by contrast, let each cultivar's underlying genetics express more freely — for better or worse, depending on what that cultivar's terpene profile looks like under stress.

What This Means for Your August Land Prep

This is a single study on one farm, with two cultivars — the authors are upfront that the findings are hypothesis-generating rather than a finished playbook. But the directional signals are specific enough to shape decisions growers are making right now, heading into spring planting.

The Honest Limitations

The research team is candid about the gaps. Soil testing was only carried out once, during an early pilot year, not repeated alongside the two seasons of cannabinoid and terpene data actually reported — so the soil characteristics and the plant chemistry weren't measured in the same years, only assumed to be broadly stable between them. The study also used a single extraction method (supercritical CO2), didn't assess the soil microbiome directly despite it being central to how cover crops are thought to work, and drew on just two cultivars from one farm. As the authors put it themselves, the findings are best read as hypothesis-generating rather than conclusive — a strong starting point for further, more tightly controlled research, not a final answer.

What the study does establish clearly is that soil preparation is not a background variable you can ignore while focusing on genetics, light, and nutrients. It is an active participant in shaping what your plant becomes — sometimes in ways that cut against simple assumptions. As land prep decisions get made this August, that's worth having in the back of your mind before the tractor — or the cover crop seed drill — goes out.

Source Study: Chacon FT, Raup-Konsavage SA, Greenland K, Gearhart R, Desai D, Zhou S, Kellogg JJ, Raup-Konsavage WM. Impact of Soil Quality on Cannabinoid and Terpenoid Content of Cannabis sativa L. J Med Act Plants. 2025;14(2-3):19–30. doi:10.7275/jmap.3150 — Center for Cannabis and Natural Product Pharmaceutics, Penn State College of Medicine, Hershey, PA, USA, in collaboration with Keystone State Testing Laboratory and Cedar Meadow Farm.
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Cannabis Bud Rot: The Rot You Don’t See Until It’s Too Late

cannabis bud rot
Cannabis Bud Rot (Botrytis): What Grey Mould Does to Trichomes & Cannabinoids
The Grower's Connect
Cultivation Science · Disease

Continuing our cultivation science arc. The last two weeks explored how to read harvest readiness. This week we look at what happens when a fungal pathogen gets there first — and what it does to the trichomes and cannabinoids before you even notice it.

Cannabis Pathology · Trichome Science · 2026 Research

Cannabis Bud Rot: The Rot You Don't See Until It's Too Late

Bud rot doesn't just destroy yield. A 2026 preprint from India documents what Botrytis cinerea actually does inside your flower — collapsing trichome structure, wiping out CBD, and rewriting the plant's cannabinoid chemistry from the inside out.

The Grower's Connect  ·  2026  ·  11 min read
−91% CBD collapse in field-infected plants (1.87% to 0.16%)
+117% THC increase in infected plants (1.04% to 2.25%)
20°C / 94%RH The peak trigger conditions for Botrytis spore production
7 days Time required for complete bud colonisation in high humidity
Listen to this article The Rot You Don't See Until It's Too Late
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Article Quick Summary: What Bud Rot Does

  • Structural Damage: Botrytis cinerea physically crushes and destroys the capitate-stalked trichomes where cannabis stores its resin.
  • Cannabinoid Shift: Infection causes a catastrophic drop in CBD levels (up to 91% reduction) while simultaneously doubling THC levels, creating massive compliance risks.
  • Terpene Loss: Essential therapeutic terpenes, notably Myrcene and Limonene, see reductions of up to 79% in infected buds.
  • Hidden Infection: Spores colonize the deep vascular tissue of the bud days before grey mould becomes visible on the surface or during the curing process.

Most cannabis growers who have dealt with bud rot (Botrytis cinerea) describe the same devastating experience. You're a week or two from harvest. The flowers look dense, healthy, and frosted with trichomes. Then you find it — a patch of grey-brown fuzz buried inside a cola, or a single bract that crumbles when you touch it. By the time grey mould is visible on the surface, it has already been inside the flower for days, possibly weeks. The damage is done.

What that damage actually looks like — chemically, structurally, at the level of the trichomes themselves — has never been fully documented. Growers have known for years that infected buds smell wrong, smoke harsh, and test lower for potency. But the precise mechanism, and the specific changes to the cannabinoid and terpene profile that infection causes, had not been studied in a controlled scientific setting. Until now.

A preprint posted to Research Square in February 2026 by researchers at CSIR-Central Institute of Medicinal and Aromatic Plants in Lucknow, India, reports the first characterisation of Botrytis cinerea infecting cannabis. More importantly, it provides the first direct measurement of what that infection does to trichome structure, cannabinoid content, and terpene profiles. The findings are unsettling, and directly relevant to anyone growing CBD-dominant or medicinal cannabis.

What is Botrytis Cinerea (Bud Rot) in Cannabis?

Botrytis cinerea is the causal agent of grey mould, universally known to cultivators as cannabis bud rot. It is a necrotrophic fungal pathogen, meaning it actively kills the host tissue it colonises rather than living within it subtly. Ranked the second most economically damaging fungal pathogen globally, it attacks over 200 plant species. Cannabis is not a special case; it is simply another highly vulnerable host.

The pathogen enters cannabis inflorescences primarily through airborne conidia — microscopic spores that are always present in the environment, whether in outdoor field conditions, indoor grow tents, greenhouses, or post-harvest drying spaces. What makes cannabis particularly susceptible is the nature of late-stage flowers: dense, moisture-retaining, and covered in glandular trichomes that the fungus exploits as entry points and nutrient sources.

Why the Curing Jar Is Not Safe

Botrytis spores persist in harvested and drying flowers. The curing environment — enclosed, slightly humid, and warm — provides the exact conditions needed to reactivate latent infections. Growers who find rot in the jar are not seeing a new contamination event; they are witnessing the final stage of an infection that began invisibly weeks earlier in the grow room.

What Causes Bud Rot? The Ideal Conditions for Botrytis Spores

To effectively prevent bud rot, cultivators need to understand environmental triggers. The Indian research team mapped the exact environmental conditions under which B. cinerea produces the most spores on cannabis inflorescences. This matters because spore load drives infection pressure — the more conidia in the air, the faster an outbreak spreads through your canopy.

Environmental Triggers for Grey Mould

  • Peak Danger Zone: Maximum spore production occurred at 20°C combined with 94% relative humidity (RH). This is the exact microclimate growers must avoid during late flower.
  • Humidity Dominates: Peak conidial counts at 94% RH reached 12.30 × 10⁶ conidia per gram — roughly five times the count observed at 60% RH. Humidity is the dominant variable.
  • Temperature Ranges: The optimal temperature range for the fungus is 15–20°C. Hot, dry conditions (30°C) suppress the pathogen, which is why bud rot is predominantly an autumn or late-season problem.
  • Cold Protection: At 10°C, essentially no spores were produced. Cold curing environments (below 15°C) with humidity below 60% are genuinely protective — confirming popular cultivator wisdom.
  • Speed of Infection: Under high humidity, complete bud colonisation occurred within just seven days of inoculation.

The practical takeaway: if your late-flower environment sits between 15°C and 25°C with a relative humidity above 85%, you are running conditions that maximise Botrytis infection success. The dense, tightly packed colas that yield the most weight are the exact structures that trap moisture and create these dangerous micro-climates.

Trichome Damage: How Botrytis Destroys Cannabis Resin

This is where the research breaks genuinely new ground. Using scanning electron microscopy, the team visualised the interaction between B. cinerea and the trichome structures of infected cannabis tissue. What they found describes a systematic dismantling of the very biological factories responsible for cannabinoid and terpene production.

Cannabis flowers carry three types of trichomes, but the capitate-stalked trichomes — the large, mushroom-shaped glands that produce the bulk of the plant's resin — were the most severely affected. Under the electron microscope, infected tissue showed:

Surface Colonisation

Extensive mycelial growth blankets the bud surface, with spore-bearing stalks growing directly from the bract tissue. The fungal mass physically displaces and crushes delicate trichomes.

Deep Vascular Invasion

The pathogen is not confined to the surface. Mycelial filaments penetrate deep into the central vascular core (xylem and phloem). This is a systemic tissue infection, not mere surface mould.

Trichome Deformation

Glandular trichomes are visibly disrupted and trapped within mycelium. The characteristic round secretory heads — which contain the valuable oils — are completely collapsed or missing.

Density Reduction

Trichome density on infected bract tissue is markedly lower than on healthy tissue. Fungal colonisation actively reduces the number of functional trichomes left on the plant.

The researchers propose a two-fold mechanism of destruction: direct physical crushing of trichomes by fungal growth, and indirect disruption of biosynthesis pathways. The plant essentially reprograms its own chemistry in a failed attempt to fight off the infection.

"The pathogen colonises the very factory that produces the plant's most valuable compounds — and the disruption is not subtle. It is a comprehensive dismantling of trichome integrity."

Cannabinoid Changes: Bud Rot Drops CBD and Increases THC

The High-Performance Liquid Chromatography (HPLC) chemical analysis is where the data becomes alarming for anyone producing medicinal hemp or CBD-dominant cannabis. The numbers reveal a dramatic, consistent chemical transformation inside the rotting bud.

Chemical Profile Shifts (Infected vs. Healthy)

  • Total CBD (Field): Crashed from 1.87% in healthy plants to 0.16% in infected plants — a devastating 91% reduction.
  • Total CBD (Greenhouse): Collapsed from 1.41% to just 0.03% — a 98% reduction. Greenhouse infections proved catastrophically damaging to CBD.
  • Total THC (Field): Increased from 1.03% in healthy plants up to 2.25% in infected plants — more than doubling the psychoactive compound.
  • Total THC (Greenhouse): Rose from 0.82% to 1.29% in infected plants. This directional shift (CBD down, THC up) was entirely consistent.

This directional shift is not a coincidence. Both CBD and THC share the same biosynthetic precursor pathway (CBGA) within the glandular trichomes. The researchers suggest the fungal infection interferes with the enzymatic steps controlling this pathway, driven by oxidative stress and the pathogen's toxic secondary metabolites (botrydial and botcinic acid).

The Compliance Risk for Hemp Growers

For commercial hemp cultivators, this finding is a major compliance risk. A CBD-dominant plant running at 1.87% CBD and 1.04% THC in healthy tissue shifts to 0.16% CBD and 2.25% THC under infection. This creates potentially illegal, "hot" non-compliant flower, destroyed crop value, and regulatory headaches — all caused by an invisible fungus.

Terpene Loss: How Grey Mould Destroys Cannabis Aromas

Gas Chromatography (GC-MS) analysis completes the picture of what cannabis bud rot truly costs. Measuring thirteen significant terpene compounds, researchers confirmed that the loss of structural trichomes directly correlates to a massive loss of therapeutic aromas.

Terpene Destruction by Botrytis

  • Myrcene: Fell from 5.78% to 1.20% in infected plants — a 79% reduction. Myrcene is critical for the "entourage effect" and anti-inflammatory properties.
  • Limonene: Dropped precipitously from 37.07% to 4.46% in greenhouse-infected plants, the largest absolute reduction of any measured compound.
  • β-Caryophyllene: Reduced from 18.54% to 13.22%. This sesquiterpene showed slight resilience but still suffered meaningful losses.

Non-infected plants presented a classic therapeutic profile: high Limonene, significant Myrcene, and strong β-Caryophyllene. Infected plants presented a distorted, hollowed-out version of this profile, stripping the flower of its medicinal value and bag appeal.

How to Prevent and Manage Cannabis Bud Rot

While this study focused on pathology, the data provides a clear roadmap for cultivators looking to prevent bud rot and protect their canopy.

Applied Cultivation Strategies

  • VPD & Humidity Control The danger zone is 15–20°C with RH above 90%. Keep your late-flower relative humidity strictly below 55% to suppress the pathogen's reproductive capacity. A single night of heavy condensation can trigger an outbreak.
  • Airflow Architecture Botrytis disperses via airborne spores. Stagnant air pockets inside dense, tightly formed colas create high-humidity micro-environments. Defoliation and aggressive under-canopy airflow are non-negotiable.
  • Early Scouting By the time you see the grey fuzz, the fungus has already penetrated the vascular tissue. Look for early symptoms: a single yellowing sugar leaf, a dark/soft bract, or an off-putting smell from an otherwise healthy cola.
  • Accelerate Harvest Because infection rapidly destroys CBD and alters THC, allowing an infected crop to finish its cycle compounds the damage. If an outbreak cannot be contained, harvesting early is chemically supported to save remaining cannabinoids.
  • Post-Harvest Hygiene Dry your cannabis in environments below 15°C and under 55% RH. Inspect curing jars daily during the first week. Curing at 60%+ RH in warm rooms will rapidly accelerate latent Botrytis spores.

Frequently Asked Questions About Cannabis Bud Rot

Can you smoke weed with bud rot?

No. Smoking cannabis infected with Botrytis cinerea (bud rot) is highly dangerous. The mould spores can cause severe respiratory infections, allergic reactions, and potentially introduce harmful mycotoxins into your lungs. Any infected plant material should be carefully bagged and discarded.

Can you save buds that have bud rot?

You cannot "cure" or save a bud once it has begun rotting. The visible grey mould is just the fruiting body; the mycelial network has already invaded deep into the vascular tissue of the flower. You must carefully cut away the infected cola, plus at least two inches of seemingly healthy tissue below it, to stop the spread.

Does bud rot spread while drying or in the curing jar?

Yes. Botrytis spores remain active after harvest. If your drying room humidity spikes above 60%, or if buds are placed into curing jars while still too wet, the latent mould spores will germinate and destroy the harvest inside the jar.

Cannabis Research Coverage — The Grower's Connect

Source Study: Yadav SS, Aftab N, Kumar B. Botrytis cinerea infection modulates trichome development and secondary metabolite biosynthesis in Cannabis sativa. Preprint posted February 6, 2026. doi:10.21203/rs.3.rs-8682864/v1 — CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow, India. This article is a preprint and has not yet completed peer review.
The Certified — The Grower's Connect  ·  thecertified.co.za
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Outdoor Cannabis in March: Preparing for the Flowering Stretch in South Africa

flowering stretch

February is winding down, and if you are growing cannabis outdoors in South Africa, you can feel the change in the air. The intense summer heat is beginning to mellow, the mornings are slightly crisper, and the days are getting shorter. For the cultivator, this signals the most critical phase of the lifecycle: The Transition to Flower.

While the last few months have been about vegetative growth and enjoying the culture, March demands a shift in focus. It is time to get serious. To maximize your yield and ensure a mould-free harvest, you need to understand exactly what is happening inside your plants right now.

Recent scientific research has changed how we view this phase. According to a groundbreaking study on Cannabis sativa architecture, “flowering” isn’t just about buds appearing; it is a massive architectural renovation of the plant. Here is what you need to know to get your garden ready for the Autumn bloom.

The Science of the Shift: It’s Not Just About Light

Most growers assume that as soon as the light hits 12/12, the plant simply decides to flower. However, the study “Architecture and Florogenesis in Female Cannabis sativa Plants“ reveals that the process is far more complex. Understanding Florogenesis (flower formation) will help you stop guessing and start growing with precision.

1. The Myth of the “Pre-Flower”

Have you noticed small calyxes with white hairs (stigmas) at the nodes of your branches even though the days are still long? Many growers mistake this for the start of the flowering stage.

The research shows that these Solitary Flowers are actually day-neutral. This means their appearance is triggered by the age of the plant, not the sun. A mature plant will produce these solitary flowers regardless of the light cycle. Seeing them is a good sign—it means your plant is sexually mature—but it does not mean the true flowering stretch has begun.

2. The Compound Raceme: Flowering is Branching

The most significant finding for growers is that the short-day photoperiod (which we approach in March) triggers intense branching, not just bud formation.

When the plant detects the shortening days, it stops growing tall (monopodial growth) and transforms its shoot tips into what scientists call a Compound Raceme.

  • What is it? The plant begins producing compressed, miniature branches packed tightly together.
  • The Phytomer: The “bud” you see is actually made up of hundreds of basic units called phytomers (reduced sugar leaves, bracts, and flowers) stacked in a condensed spiral.

This means that during the March transition, your plant is frantically building a new, heavy internal structure.

flowering stretch

Your March Grow Guide: 4 Steps to a Massive Harvest

Now that we understand that the plant is undergoing a structural overhaul, here is your checklist to support this architectural shift.

1. Inspect the Apex, Not the Nodes

Stop looking at the bottom of the branches for signs of flowering. To catch the transition early, look at the apical meristem (the very tip of the main shoots).

  • What to look for: When the growth at the tip becomes tight, clustered, and intricate, the plant is building its compound raceme. This signals the start of the “stretch.”
  • Action: This is your last chance to do any final training. Once these tips harden into structure, the plant’s shape is set.

2. Structural Support is Mandatory

Because the plant is about to build heavy, condensed branches, it needs physical support. The architectural shift identified in the study proves that the plant becomes top-heavy.

  • Action: If you haven’t installed netting (SCROG) or staked your plants, do it immediately. March winds in South Africa can be brutal. Support the structure now, because you won’t be able to lift heavy colas later without stressing the plant.

3. Adjust Nutrition for Branching (Don’t Dump the Nitrogen Yet)

A common mistake in March is cutting out Nitrogen (N) too early and switching straight to a Bloom Booster (P-K).

  • The Science: Since the transition involves rapid, condensed branching, the plant still requires Nitrogen to build this new structure.
  • Action: Switch to a transition feed. You need a balanced diet that supports structural growth (Nitrogen) while introducing the Phosphorus and Potassium needed for the early reproductive phase. Starving the plant of N now will result in weak branches that cannot support heavy flowers.

4. Maximise Resin Surface Area

The research noted that glandular trichomes (the resin factories containing THC and Terpenes) appear most profusely on the perigonal bracts (the leaf-like tissue casing the ovary).

  • The Goal: A healthier architectural structure produces more bracts. More bracts equal more surface area for resin.
  • Action: Ensure decent airflow and low humidity around your plants. This prevents mould and allows the plant to focus energy on producing these resin-rich bracts rather than fighting off pathogens.
flowering stretch

Conclusion: Respect the Architecture

As we head into March, look at your outdoor crop with fresh eyes. They aren’t just “making flowers”; they are rebuilding their entire internal architecture to support the next generation.

By respecting this biological process—supporting the structure, timing your nutrients, and knowing what to look for—you are setting yourself up for a successful, heavy harvest in May.

Happy Growing, South Africa. Let the season begin.

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The Heroes of Soil: Mastering Humic and Fulvic Acids

humic and fulvic acids

This week, we are continuing our deeper dive into plant growth regulators. Nutrients are such an interesting topic and so misunderstood. I hope the last few weeks have cleared some are regarding PGRs, Group fertilisers or natural hormones like gibberellic acid. However, today we are focusing our attention on the heroes of organic plant growth regulators: humic and fulvic acids. These complex organic molecules are the lifeblood of fertile soil, acting as powerful biostimulants and nutrient managers. In South Africa, where many of our soils are alkaline and can “lock up” essential micronutrients, understanding and utilising these substances can be the difference between a good grow and an exceptional one.

For many cultivators, these terms might sound technical, but their function is beautifully simple: they make your soil and your cannabis plants work better, together. Let’s unravel the mystery of humic and fulvic acids, explore how they function, and learn how growers can leverage their power for unparalleled plant health and vitality.

What are Humic and Fulvic Acids? The Essence of Soil Organic Matter

At its core, all fertile soil contains Soil Organic Matter (SOM), the decomposed remains of countless generations of plants and microorganisms – read more here. Through a natural process called humification, this organic matter is transformed into stable, complex compounds known as humic substances. These substances are the main component of soil active carbon and are absolutely critical for soil fertility, water retention, and overall environmental health.

Humic substances are broadly classified into three main fractions based on their solubility:

  1. Humins: The largest molecules, which are insoluble in both acidic and alkaline conditions, form the stable, structural backbone of soil humus.
  2. Humic Acids (HA): Large, complex molecules that are soluble in alkaline conditions but precipitate (become solid) in acidic conditions.
  3. Fulvic Acids (FA): The smallest and most chemically active molecules, which remain soluble across all pH ranges, from highly acidic to highly alkaline.

For agricultural purposes, we are primarily interested in humic and fulvic acids. These substances are extracted from rich sources of decomposed organic matter like leonardite (a type of oxidised coal), peat, compost, and vermicompost. In South Africa, they fall under the category of Group 3 Fertilizers according to Act 36 of 1947, classifying them not as direct nutrient sources, but as powerful soil enhancers and plant biostimulants.

As a side note, it is also important to know that when we refer to humic acids or fulvic acids, there are various kinds of them. The quality is very dependent on the sourcing of the acids. It is important as a grower to look at the bottle and read the labelling. Do research and ask critical questions about the additives we will be using in our grows. No one humic acids are alike. Keep that in mind.

humic and fulvic acids

The Dynamic Duo: Understanding the Difference Between Humic and Fulvic Acid

While often sold together, humic and fulvic acids have distinct structures and perform different, yet complementary, roles in your soil. Understanding this difference is key to using them effectively in your cannabis grow.

Think of it this way: Humic Acid is the soil’s architect and structural engineer, while Fulvic Acid is the high-speed nutrient courier.

Humic Acid (The Architect): Humic acids are large, high-molecular-weight molecules with a dark brown to black colour. Their primary strength lies in improving the physical and biological properties of the soil. They are less chemically reactive than fulvic acids but provide long-term structural benefits. Their functions include:

  • Improving Soil Structure: Humic acid binds to clay, silt, and sand particles, creating stable soil aggregates. This process improves soil aeration, prevents compaction, and enhances water infiltration, allowing your cannabis roots to breathe and grow without restriction.
  • Enhancing Water Retention: The complex structure of humic acid acts like a sponge, holding onto water molecules and making them available to plant roots for longer periods. This is a massive advantage in South Africa’s often dry and water-scarce regions.
  • Boosting Cation Exchange Capacity (CEC): Humic acids possess a high number of negative charges, which act like magnets for positively charged nutrients (cations) such as calcium, magnesium, potassium, and essential micronutrients. This high CEC prevents these vital nutrients from leaching away, keeping them available in the root zone for your cannabis plants to absorb.
  • Stimulating Microbial Life: Humic acid provides a rich carbon source for beneficial soil microorganisms, like mycorrhizal fungi and nitrogen-fixing bacteria. A thriving microbial community enhances nutrient cycling, improves soil fertility, and can even help suppress plant pathogens.

In essence, humic acid builds a better home for your plants, creating a robust and resilient soil ecosystem.

Fulvic Acid (The Nutrient Courier): Fulvic acids are much smaller, low-molecular-weight molecules with a yellow to amber colour. They are highly soluble and incredibly chemically reactive, making them masters of nutrient delivery and direct plant stimulation.

  • Superior Chelation and Micronutrient Availability: Fulvic acid’s greatest superpower is its ability to chelate metal ions. Chelation is a process where the fulvic acid molecule “claws” onto micronutrients like iron, manganese, zinc, and copper, forming a stable, soluble complex. This is critically important in South Africa’s alkaline and calcareous soils, where high pH typically “locks up” these micronutrients, making them unavailable to plants. Fulvic acid keeps them in a plant-available form, directly combating common deficiencies.
  • Direct Plant Absorption and Biostimulation: Due to their small size, fulvic acid molecules can be easily absorbed by plant roots and even leaves (when used as a foliar spray). Once inside the plant, they act as biostimulants, improving nutrient uptake, enhancing root development, increasing resistance to stress (like drought and salinity), and even influencing the plant’s natural hormone levels.
  • The Paradigm Shift in Understanding: Recent cutting-edge research has revealed a paradigm shift in how we understand fulvic acid’s efficacy. A study published in Scientific Reports demonstrated that its incredible ability to mobilize manganese (Mn)—a crucial micronutrient—is driven not just by its acidic functional groups, but by its hydrophobic, lignin-derived molecular structure. This means the specific architecture of the fulvic acid molecule, particularly its alkyl/O-alkyl ratio, plays a more significant role than previously thought. This underscores that the quality and structure of the humic substance are paramount.

In short, fulvic acid is the express delivery service, ensuring your cannabis plants get the vital micronutrients and biostimulant boost they need to thrive.

humic and fulvic acids

Practical Applications for South African Cannabis Growers

Understanding the distinct roles of humic and fulvic acids allows you to apply them strategically to your cannabis grow for maximum benefit.

When and How to Use Humic Acid:
Humic acid is your go-to for building a healthy soil foundation. It is best applied during soil preparation or as a regular soil drench.

  • Prepping Your Beds: When preparing your outdoor beds or mixing your potting soil, incorporate a high-quality granular or liquid humic acid product. This will immediately begin to improve soil structure, water retention, and create a fertile environment for root establishment.
  • Improving Existing Soil: For established plants, regular application of humic acid as a soil drench can help maintain soil health, buffer pH, and enhance the efficiency of your other fertilizers. It revitalises tired soils and supports a thriving root-zone ecosystem.

When and How to Use Fulvic Acid:
Fulvic acid is your tool for targeted nutrient delivery and biostimulation, particularly useful during key growth stages or to address specific issues.

  • Combating Micronutrient Lockout: In South Africa’s alkaline soils, fulvic acid is a non-negotiable ally. Regular application via fertigation (mixing into your water) or as a soil drench will keep essential micronutrients like iron, manganese, and zinc available to your cannabis plants, preventing the tell-tale signs of deficiency like yellowing leaves (chlorosis).
  • Foliar Feeding for a Quick Boost: Because of its small molecular size, fulvic acid is highly effective as a foliar spray. Spraying a dilute solution directly onto the leaves allows for rapid absorption, providing an immediate biostimulant effect and delivering micronutrients directly to where they are needed. This is excellent for giving your plants a boost during vegetative growth or to correct deficiencies quickly.
  • Enhancing Seed Germination and Cloning: Soaking seeds or treating fresh cuttings with a dilute fulvic acid solution can enhance germination rates and promote rapid root development, giving your young plants a vigorous start.

Dosage and Quality Matter:
The research is detailed: application rates matter. While conventional low rates of humic and fulvic acids offer general soil health benefits, recent studies show that higher application rates can have a dramatic impact on micronutrient availability. One study demonstrated that a high application of a specific fulvic acid increased manganese availability by up to 3061% in a calcareous soil, while lower rates had negligible effects. This suggests that for correcting specific deficiencies, a more targeted, higher-dose approach might be necessary.

Furthermore, studies on cannabis have shown that nutritional supplements, including humic acid, can have complex, organ-specific effects on the plant’s chemical profile. For example, one study found that humic acid supplementation, while reducing the natural spatial variability of cannabinoids, actually lowered THC and CBD concentrations in the top flowers. This underscores that these substances are powerful modulators, not just simple “boosters,” and their effects should be observed carefully.

Humic and fulvic acids

Cultivating a Thriving Ecosystem: The Final Word

Moving beyond simply feeding your plants to actively nurturing your soil ecosystem is the key to unlocking true excellence. Humic and fulvic acids are not magic bullets, but they are powerful, natural tools that work in harmony with your plant’s biology and your soil’s chemistry.

humic and fulvic acids

By embracing humic acid as the architect of a healthy soil foundation and fulvic acid as the efficient courier of vital micronutrients, you are adopting a holistic approach that fosters resilience, vitality, and the full expression of your cannabis plant’s unique terroir. As we continue to celebrate the incredible potential of Cannabis sativa L., let’s remember that the journey to a legendary harvest begins right beneath our feet, in the rich, living soil that sustains it all.

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Unlocking Growth with Gibberellic Acid in Cannabis Cultivation

Gibberellic acid
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The cannabis season in South Africa is now in full swing, a testament to the hard work and passion of growers across our diverse landscapes. We’ve explored the profound influence of terroir on our unique strains, celebrated local scientific breakthroughs like the discovery of flavoalkaloids in cannabis leaves by Stellenbosch University, and even demystified the ancient rhythms of celestial gardening that guide many cultivators. Now, as our plants stretch towards the sun, reaching for their fullest potential, it’s time to delve into one of the most powerful, yet often misunderstood, tools in a grower’s arsenal: Gibberellic Acid (GA3).

While many growers are familiar with macro-nutrients (NPK) and the importance of a balanced feeding schedule, the role of plant hormones – or Plant Growth Regulators (PGRs) – introduces a fascinating layer of biological control. Gibberellic Acid, in particular, is a natural, tetracyclic diterpenoid compound that acts as a profound architect within the plant, orchestrating a myriad of growth and developmental processes. Understanding how GA3 works, its benefits, and its complex interactions within the cannabis plant is crucial for any South African cultivator looking to refine their techniques and maximise their harvest.

This week, we’ll unravel the mysteries of Gibberellic Acid, exploring its powerful functions, its nuanced impact on the cannabis plant’s chemistry, and how responsible application, guided by local regulations and scientific insights, can help you achieve new heights in your cultivation journey.

Gibberellic Acid: Nature’s Growth Orchestrator

At its core, Gibberellic Acid (GA3) is a naturally occurring plant hormone, formally classified as a tetracyclic diterpenoid. Its journey into scientific recognition began in the 1930s when Japanese scientists linked it to a fungal disease, “foolish seedling,” which caused rice plants to grow abnormally tall. This observation revealed GA3’s potent ability to stimulate dramatic growth, quickly elevating it to a significant area of plant science research.

In the context of South African agriculture, Gibberellic Acid, like other Plant Growth Regulators (PGRs) such as auxins and cytokinins, is classified under Group 3 fertilisers by the Department of Agriculture, Forestry and Fisheries (DAFF) Act 36 of 1947. This classification is vital: unlike Group 1 and 2 fertilisers that primarily supply bulk nutrients (NPK), Group 3 products like GA3 are not primarily about feeding the plant directly. Instead, they act as regulators, influencing the plant’s physiological processes, often in minute quantities, to improve growth, yield, or overall plant and soil conditions. This means GA3 is a powerful tool for directing growth, rather than just fuelling it, requiring a precise and informed approach to its use.

Gibberellic acid

The Inner Workings: How GA3 Orchestrates Cannabis Development

Gibberellic Acid is a master orchestrator of plant development, involved in a wide array of processes that directly impact a cannabis plant’s life cycle. Its action is complex, influencing everything from the very first spark of life in a seed to the final stages of flower formation.

GA3’s effects are mediated through intricate biochemical pathways within the plant. Its biosynthesis occurs primarily via two pathways: the mevalonate (MVA) pathway and the methylerythritol phosphate (MEP) pathway, involving key enzymes like 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and 1-deoxy-D-xylulose 5-phosphate synthase (DXS) [cite: Mansouri et al. 2009 & 2011]. These pathways are responsible for producing a wide range of isoprenoids, including not only GA3 itself but also crucial compounds like terpenes, phytosterols, and photosynthetic pigments.

Key functions of Gibberellic Acid in plants include:

  • Breaking Seed Dormancy and Enhancing Germination: GA3 is a potent stimulant for seed germination, playing a critical role in overcoming seed dormancy. It promotes the production of hydrolytic enzymes, like α-amylase, which break down stored food reserves in the seed, providing energy for the emerging embryo. For cannabis growers, especially those looking for vigorous starts following the Spring Equinox, GA3 can be a valuable aid for consistent germination.
  • Promoting Stem Elongation: One of GA3’s most well-known effects is its ability to stimulate rapid stem and internode elongation, contributing significantly to a plant’s overall height. This occurs by stimulating cell division and expansion, leading to taller, more open plant architecture.
  • Influencing Flowering and Sex Expression: GA3 plays a complex role in flower development and sex expression. In many species, it’s involved in the transition from vegetative to flowering phases and is essential for both male and female fertility. Interestingly, GA3 can promote a male tendency in some plants, a factor that can be critical for cannabis breeders looking to develop specific genetics.
  • Embryo Development: It’s also a key regulator of the maturation phase of embryos, interacting antagonistically with abscisic acid (ABA) to balance growth and dormancy.

While GA3’s exact movement and targeted tissues for action are still subjects of ongoing scientific investigation, its profound influence on these foundational plant processes is undeniable.

The Unseen Hand: GA3’s Nuanced Impact on Cannabis Chemistry

Beyond its visible effects on growth, Gibberellic Acid exerts a subtle, yet significant, influence on the internal chemistry of the cannabis plant, impacting the very compounds that define its unique “terroir” – its aroma, potency, and therapeutic profile. Research into GA3’s effects on Cannabis sativa L. reveals a complex interplay, often depending on the plant’s developmental stage and the specific GA3 concentration.

Studies have shown that GA3 treatment can lead to:

  • Modulation of Photosynthetic Pigments and Antioxidants: Research has indicated that GA3 can decrease chlorophyll and carotenoid content in cannabis leaves. Interestingly, this might coincide with an increase in α-tocopherol (a form of Vitamin E), a lipophilic antioxidant. This suggests a complex rebalancing of metabolic pathways within the plant, where GA3 might redirect resources.
  • Boosting Phytosterol Production: GA3 treatment generally stimulates the MVA pathway, leading to an increase in phytosterols like squalene, stigmasterol, β-sitosterol, and campesterol. These compounds are vital for cell membrane structure and have their own health benefits, as we’ve noted when discussing the nutritional value of hemp seeds.
  • Complex Effects on Terpenes, THC, and CBD: This is where the impact of GA3 becomes particularly intricate for cannabis cultivators.
    • Early research (Mansouri et al. 2009) conducted at the flowering stage indicated that GA3 treatment decreased THC content in both leaves and flowers, a stronger effect observed in male plants.
    • However, a later study by the same researchers (Mansouri et al. 2011) at the vegetative stage showed that while lower concentrations (50 µM) had no effect, a higher concentration (100 µM) of GA3 actually increased THC and CBD content in cannabis leaves compared to control plants. This apparent contradiction highlights the critical importance of the plant’s developmental stage and GA3 concentration. The researchers suggest that the increase in THC/CBD might not be a direct GA3 effect but an interaction with other plant hormones, like ethylene, which GA3 can stimulate.
    • Regarding terpenes, GA3 treatment has been shown to decrease the overall number and percentage of monoterpenes and sesquiterpenes in cannabis, though specific sesquiterpenes exhibited mixed responses, with some increasing while others decreased. This complex modulation underscores GA3’s role as an “unseen architect,” subtly shifting the plant’s unique aromatic and therapeutic fingerprint.

These findings reveal that GA3 does not act as a simple booster for cannabinoids or terpenes; rather, it’s a powerful modulator that influences their biosynthesis pathways in complex, sometimes opposite, ways depending on the developmental stage and specific environmental interactions. This makes its application a nuanced art, requiring careful consideration and an understanding of the intricate chemical dance within the plant.

Gibberellic acid

Strategic Application for South African Cannabis Growers

For South African cannabis cultivators, understanding Gibberellic Acid as a Group 3 Plant Growth Regulator opens up new possibilities for fine-tuning their grow operations. However, this power comes with the responsibility of precise and informed application.

Key Benefits of Responsible GA3 Use:

  • Vigorous Starts: For difficult-to-germinate cannabis seeds, a carefully calibrated GA3 treatment can significantly improve germination rates, giving your seedlings a strong start, especially crucial as we move further into the season.
  • Accelerated Vegetative Growth: GA3 can be used to promote rapid stem elongation and increase internode spacing during the vegetative phase. This can be beneficial for specific training techniques or for achieving desired plant architectures, influencing the overall florogenesis, or flower development, as we touched on when discussing plant structure.
  • Breeding and Sex Modulation: For breeders, GA3’s ability to influence sex expression can be a valuable tool in creating specific crosses or developing feminised seeds, although this is an advanced application requiring expert knowledge.
  • Stress Resilience (Indirectly): While GA3 directly influences growth, its role in plant hormone pathways can indirectly enhance resilience. For example, some studies on other plants show GA3 improving growth under heavy metal stress, suggesting a potential role in helping plants cope with various abiotic challenges. This aligns with using other Group 3 enhancers like KELPAK, a seaweed extract, which helps plants manage stress and improve nutrient uptake.
Gibberellic acid

Navigating Responsible Application in South Africa:

As a Group 3 fertiliser, GA3 requires particular attention to application rates. DAFF guidelines mandate rigorous efficacy studies, phytotoxicity tests, and toxicological studies for all PGRs. This means:

  1. Strict Adherence to Guidelines: Always follow the manufacturer’s recommended application rates diligently. Over-application can lead to undesirable effects, such as excessive stem elongation (often called “stretch”), reduced branching, or even negative impacts on flowering and yield.
  2. Product Efficacy and Safety: Prioritise products from reputable suppliers who can provide documentation of their efficacy and safety studies. These studies, often conducted in controlled environments (greenhouses) or fields, ensure the product performs as claimed without harming plants, humans, or the environment. This is about protecting your crop, your health, and our precious South African soil.
  3. Understanding Phytotoxicity: Always be aware of potential phytotoxicity. GA3, if misapplied, can cause negative effects like stem malformation, reduced chlorophyll, or altered flower development. Always test on a small sample first.
  4. Targeted Application: The effects of GA3 are highly dependent on the plant’s developmental stage and concentration. Understand when to apply it for specific outcomes – e.g., for germination, vegetative growth, or sex modulation – rather than as a general growth booster.

Cultivating Excellence, Responsibly, in South Africa

The intricate dance of plant hormones like Gibberellic Acid offers a powerful lens through which to view cannabis cultivation. It’s a reminder that truly mastering the art of growing involves not just feeding the plant, but understanding its complex biology and how to subtly guide its development.

As South African cannabis cultivators, embracing GA3 as a Group 3 PGR is a step towards precision farming, allowing you to influence growth, architecture, and even the chemical signature of your plants in a targeted manner. By blending the profound insights from local scientific research – from the hidden world of flavoalkaloids in cannabis leaves to the intricate mechanisms of plant hormones – with a deep respect for responsible application and regulatory compliance, you can unlock unparalleled levels of quality and yield.

Let this grow season be one of informed exploration. May your understanding of Gibberellic Acid empower you to cultivate exceptional cannabis, reflecting the unique terroir of South Africa and the scientific excellence that flourishes on our soil.

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What are Fertiliser Groups: Understanding nutrients

fertilisers
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In South Africa’s flourishing cannabis landscape, where the energy of grow season is palpable, and cultivators strive for excellence – from nurturing monster outdoor crops to dialling in precision greenhouse environments – every decision counts. We’ve celebrated the plant’s inherent value, delving into the nutritional power of hemp seeds, marvelling at discoveries like the flavoalkaloids in cannabis leaves by Stellenbosch University, and embracing the cosmic rhythms that guide traditional planting. Now, it’s time to address a foundational element critical to every grower’s success: fertilisation.

Choosing the right nutrients for your cannabis plants can feel like navigating a complex maze. The market is saturated with products, each promising optimal growth and bountiful harvests. To make informed decisions, it’s essential to understand the regulatory framework that governs these products in South Africa – specifically, the Fertilisers, Farm Feeds, Agricultural Remedies and Stock Remedies Act, 1947 (Act No. 36 of 1947), overseen by the Department of Agriculture, Forestry and Fisheries (DAFF). This framework categorises fertilisers into distinct groups, guiding their composition, claims, and application.

This week, we’ll demystify these fertiliser groups, with a particular focus on Group 3 fertilisers. Many growers might not fully grasp that certain organic-derived products, including powerful hormone extracts, fall into this fascinating category. Understanding these classifications is key to selecting the right products that support healthy, high-quality cannabis, in harmony with both scientific principles and regulatory compliance.

The Foundation: South Africa’s Fertiliser Groupings

Under Act 36 of 1947, fertilisers in South Africa are broadly categorised into three main groups based on their primary function and nutrient composition. This classification helps both regulators and growers understand a product’s intended purpose and the claims it can legally make. A “fertiliser,” as defined by the Act, is any substance or organism intended to improve or maintain plant growth, yield, or the physical, chemical, or biological conditions of the soil.

Group 1 and Group 2 Fertilisers: The Core Nutrient Providers

These two groups largely encompass what most growers recognise as conventional fertilisers, focusing on the direct supply of major plant nutrients.

  • Group 1 Fertilisers are those containing a total of 100 g/kg or more of Nitrogen (N), Phosphorus (P), or Potassium (K), or any combination thereof. These are your high-impact, chemically compounded or enriched organic fertilizers designed to provide substantial amounts of the essential macro-elements that cannabis plants require in large quantities for vigorous growth, flowering, and fruit development. Most of the time, these will be the synthetic nutrients you are used to seeing on the market. But note that there are group 1 blends that are organic blends. These products are more available in huge blends from major Agri farm suppliers. 
  • Group 2 Fertilisers include those with a total of less than 100 g/kg of N, P, or K, or those that provide other recognised plant nutrients in acceptable amounts. These often include products focusing on intermediate macro-elements like Calcium, Magnesium, and Sulphur, or specific trace elements. While still nutrient providers, their concentration of NPK is lower than Group 1. Products like “Bonemeal” or “Iron Chelate”, which focus on specific nutrient delivery or soil amendments, would typically be found here if their NPK levels are below the Group 1 threshold. Thus, we normally associate group two with a more organic fertigation. But it is not to say that all group 2 fertilisers are organic in composition. 

Both Group 1 and Group 2 fertilisers are vital for directly feeding your cannabis plants, ensuring they receive the NPK ratios necessary for healthy vegetative growth, robust root systems, and prolific flower development, as we discussed when exploring cannabis’s nutritional needs and terroir.

fertiliser

Group 3 Fertilisers: The Holistic Enhancers and Stimulants

This is where the distinction becomes particularly interesting for cannabis cultivators aiming for a truly holistic approach to plant health and maximising specific traits – from stress resilience to enhanced resin production. Group 3 fertilisers are defined as any natural or synthetic substance or organism that improves the growth or yield of plants, or the physical, chemical, or biological conditions of the soil, and does not qualify for registration as a Group 1 or 2 fertiliser based on NPK content. 

Unlike Groups 1 and 2, which primarily supply nutrients, Group 3 products often enhance the plant’s ability to utilise nutrients, improve its environment, or directly stimulate physiological processes. This broad definition encompasses a diverse range of innovative products crucial for modern cannabis cultivation.

Within Group 3, we find several key categories:

  • Biofertilisers: These are living organisms that enhance plant growth by improving nutrient availability or uptake. This includes beneficial fungi (like mycorrhizae) and bacteria that colonise the root zone, improving nutrient cycling and pathogen resistance. For cannabis, this means a healthier root environment, leading to stronger, more resilient plants, a concept deeply aligned with nurturing terroir. Our FPJ and FFJ blogs would give a great guide to homemade biofertilisers. 
  • Soil Enhancers (Soil Conditioners): These products improve the physical properties of the soil, such as water retention, cation exchange capacity (CEC), and hydraulic conductivity. They don’t directly feed the plant, but create a better medium for roots to thrive. Examples include humic and fulvic acids, which improve nutrient absorption and soil structure, or peat and palm peat for enhanced water holding capacity and aeration – crucial for cannabis root development, as we discussed in the context of the Spring Equinox. Also consider our work on IMO, Korean natural farming too. Some awesome guides for homemade quality.
  • Seaweed Containing Products: Extracts from seaweed, like KELPAK or NATRAGRO from Starke Ayres, are rich in natural growth hormones and trace elements. They are classified as Group 3 because their primary function is plant stimulation and stress alleviation, rather than major NPK provision. They assist plants through stresses like heat, drought, and disease, and improve NPK uptake. 
  • Plant Growth Regulators (PGRs): This is a critical category, and one that often causes confusion. PGRs include both natural and synthetic substances like Auxins, Brassinosteroids, Cytokinins, and Gibberellic acid. These compounds directly influence plant physiological processes such as root development, cell elongation, branching, and flowering. A common misconception is that if a product is “organic” it can’t be a PGR or a Group 3 fertiliser. However, many hormone extracts are organically derived but still function as PGRs, falling squarely into Group 3 due to their role in regulating growth rather than primarily supplying bulk NPK. Our understanding of cannabis architecture and florogenesis, highlighted by studies like those from Spitzer-Rimon et al., underscores the intricate hormonal control over plant development, making PGRs potent tools for cultivators.
  • Fertiliser Coatings and Inhibitors: These products improve the efficacy of other fertilisers by controlling nutrient release or increasing their residency in the soil. Nitrogen inhibitors, for example, prevent nitrogen loss, making fertilisers more efficient.
  • Products of Plant and Animal Origin (excluding bone and blood meal): This category includes various natural materials that improve soil conditions or plant growth, provided they meet specific safety and efficacy standards. Any moringa-based product, for example, Phytostim.
  • Novel Products: This catch-all category allows for the registration of new, innovative substances that improve plant or soil conditions, ensuring the regulatory framework can adapt to scientific advancements.
fertiliser

Why Group 3 Fertilisers are Essential for Cannabis Growers

For South African cannabis cultivators, embracing Group 3 fertilisers isn’t just about compliance; it’s a strategic move to optimise plant health, yield, and the expression of unique cannabis terroir.

  • Holistic Plant Health: Group 3 products work in synergy with conventional fertilisers. While NPK fertilisers provide the building blocks, Group 3 enhancers improve the very environment and mechanisms through which these blocks are absorbed and utilised. This leads to overall healthier, more vigorous plants.
  • Enhanced Terroir Expression: As we discussed, terroir is influenced by climate, soil, and genetics. Soil enhancers, biofertilisers, and seaweed extracts can optimise the soil’s biological activity and nutrient availability, allowing your cannabis plants to fully express their unique genetic potential, including those intricate terpene and cannabinoid profiles that make our local strains so distinctive.
  • Stress Resilience: PGRs and seaweed-based products, like Kelpak, are particularly effective in helping plants cope with environmental stressors such as drought, heat, and disease – common challenges in many South African climates. Stronger, healthier plants are naturally more resistant to mould and pests, a wish for our outdoor growers.
  • Optimised Growth Cycles: PGRs can be invaluable for fine-tuning plant development. For instance, specific hormones can be used to promote robust root growth in seedlings or to encourage denser branching in vegetative plants, influencing the plant architecture we saw discussed in studies on cannabis florogenesis. This is especially relevant for our greenhouse growers looking for smooth tunnel flower and a dialled-in setup.
  • Root Development and Nutrient Uptake: Humic and fulvic acids significantly improve nutrient uptake efficiency and foster robust root systems. As we learned from the Spring Equinox discussion, strong root development is fundamental for a healthy plant.
fertiliser

Navigating Your Choices: A Responsible Grower’s Guide

Selecting the right fertilisers requires an informed approach.

  1. Understand Your Plant’s Needs: Start with the basics. Cannabis has specific NPK requirements that change during its vegetative and flowering phases. We have written extensively on nutrients. How to ensure the correct NPK for your plants. So check those out if you are stuck. 
  2. Read Labels Carefully: All registered fertilisers must detail their composition, application rates, and usage instructions. Look for the NPK sequence (e.g., 2:3:2), percentages of macro-elements, and lists of micro-elements. Pay attention to application rates, whether for foliar spray or soil drench, and apply them diligently to avoid over-application or under-application. If there are none of these things on the label, then you need to ask more questions. Use with caution.
  3. Prioritise Efficacy and Safety: For Group 3 fertilisers, DAFF requires rigorous efficacy studies (scientific reports based on statistical analyses, often conducted in field, greenhouse, or laboratory settings) and toxicological studies to ensure the product has no harmful effects on plants, humans, animals, or the environment. This includes testing for phytotoxicity (negative effects on plant development, colour, yield, etc.). Always choose products from reputable suppliers who can provide this documentation.

Cultivating Excellence in South Africa

The journey of growing cannabis in South Africa is a dynamic blend of traditional wisdom and cutting-edge science. By understanding the nuances of Group 3 fertilizers – from biofertilizers and soil enhancers to plant growth regulators derived from natural sources – growers can make informed choices that promote not just growth, but true plant vitality, stress resistance, and the full expression of their unique cannabis terroir.

fertiliser

As you prepare your setups and nurture your plants this season, let this knowledge empower you. Choose your fertilisers wisely, respecting both the plant’s needs and the regulatory framework that ensures quality and safety. May your cultivation efforts reach new heights, yielding healthy, high-quality cannabis products that truly reflect the spirit of South African excellence.

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What are Auxins?

Auxins
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In the intricate world of cannabis cultivation, where every factor from genetics to environment plays a pivotal role, understanding plant hormones is akin to mastering the plant’s secret language. Last week, we delved into the mysteries of Florigen, the elusive hormone responsible for triggering the flowering cascade. This week, our spotlight turns to another foundational class of plant growth regulators: auxins. These remarkable compounds are primary architects of plant development, stimulating growth in myriad ways and offering discerning growers powerful tools to sculpt their cannabis plants for optimal health and bountiful yields. By comprehending the mechanics of auxins, cultivators can fine-tune their strategies, leading to more robust plants, enhanced rooting, and precisely controlled plant architecture, especially in the nuanced environment of a cannabis garden.

What are Auxins? The Master Regulators of Plant Growth

Auxins are fascinating endogenous molecules, naturally occurring within plants at incredibly low concentrations, yet acting as potent signalling compounds that orchestrate a wide spectrum of plant development and physiological processes. They are not nutritional elements, but rather sophisticated messengers, dictating how a plant grows, forms, and responds to its environment. The most prominent natural auxin is Indole-3-acetic acid (IAA), a compound primarily synthesised in rapidly dividing tissues such as the apical meristems of shoots, young leaves, and developing This production at the growing tips ensures a continuous supply to drive various growth initiatives. Beyond these aerial production sites, IAA is also found in the root tips, highlighting its pervasive influence throughout the plant’s structure.

While IAA is the plant’s native powerhouse, its chemical instability when extracted makes it less practical for commercial application. This is where synthetic auxins come into play, offering stable and effective alternatives. Among the most commonly utilised synthetic auxins are 1-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA).] These synthetic counterparts mimic the biological effects of natural auxins and are frequently found as active ingredients in commercial rooting compounds due to their enhanced stability and longer-lasting effects. The subtle chemical differences between natural IAA and synthetic NAA, particularly in their steric properties—the larger naphthalene ring of NAA versus the indole system of IAA—can influence how they interact with plant cell membranes. Natural IAA, with its more compact structure, tends to penetrate lipid monolayers more readily than NAA. Despite these structural variations, both natural and synthetic auxins fundamentally promote plant growth through their influence on cell elongation and division, making them indispensable regulators in plant biology.

auxins

The Diverse Roles of Auxins in Cannabis Development

Auxins exert a profound influence on virtually every aspect of cannabis development, from the hidden networks beneath the soil to the towering stems reaching for light. One of their most well-known functions is the maintenance of apical dominance, a phenomenon where the main central stem grows more vigorously, suppressing the growth of lateral buds. This occurs because auxins, particularly IAA, are produced at the growth tips of the main shoot and are transported downwards. The highest concentrations of auxin near the apex inhibit the development of side branches, channelling the plant’s energy into vertical growth, often resulting in a single, dominant main cola. Understanding this mechanism is crucial for growers employing pruning techniques aimed at creating bushier plants.

Conversely, auxins are equally critical below ground, playing a central role in root development. They are the primary drivers for initiating adventitious and lateral roots, which are essential for forming a robust root system. A strong, expansive root network is fundamental for efficient nutrient and water uptake, anchoring the plant, and enhancing its overall resilience. Auxins also guide the direction of root growth, ensuring they delve deeper into the substrate to access vital resources and contribute to the healing and repair of damaged root tissues.

The interplay between auxins and other plant hormones, particularly cytokinins, forms a complex regulatory system. While auxins generally promote root growth and suppress shoot development, cytokinins, produced primarily in the roots, tend to favour shoot growth and inhibit root formation. This intricate, often antagonistic, relationship means that the ratio of auxins to cytokinins within different plant tissues dictates specific developmental pathways, such as meristem activity and shoot branching patterns. This delicate balance is vital; for instance, auxin stimulates the development of lateral roots while cytokinins can inhibit it, showcasing their opposing yet complementary roles in shaping the plant’s architecture.

Beyond structural development, auxins also impact fundamental physiological processes like photosynthesis and transpiration. Studies have indicated that auxins can influence the intensity of these processes, potentially leading to increased carbon dioxide assimilation and higher chlorophyll content in plant leaves. This enhancement can be attributed to auxins stimulating the activity of photosynthetic enzymes, thereby contributing to the plant’s overall metabolic efficiency and energy production. By affecting such a broad spectrum of functions, auxins truly stand as master regulators, influencing everything from the plant’s outward form to its internal metabolic machinery.

Auxins

Harnessing Auxins for Optimal Cannabis Cultivation: Practical Applications for Growers

For cannabis cultivators, understanding auxins translates directly into actionable strategies for improving plant health, managing growth, and ultimately boosting yields. One of the most common and impactful applications of auxins is in propagation, specifically for cloning. When taking cuttings, the application of auxin-rich rooting hormones, typically containing synthetic auxins like IBA or NAA, is crucial. These hormones are absorbed by the cut stem, stimulating the formation of adventitious roots, which are new roots developing from non-root tissues. This process significantly increases the success rate of rooting, allowing growers to rapidly multiply desirable genotypes and establish new plants with robust root systems.

Auxins also offer powerful tools for controlling plant architecture and height. While auxins naturally promote vertical growth by maintaining apical dominance, growers can manipulate this effect. The traditional method of “pinching off” or “topping” the main shoot apex directly removes the primary source of auxin. This disruption releases the lateral buds from inhibition, allowing them to develop into new branches, leading to a bushier, more compact plant with multiple colas rather than a single dominant one. This technique is especially beneficial for maximising light penetration and airflow within the canopy, thereby improving overall yield potential.

Research on the exogenous application of synthetic auxins presents a more nuanced picture, highlighting the importance of context and genotype. In one study involving industrial hemp (Bialobrzeskie variety), spraying with 1-naphthaleneacetic acid (NAA) surprisingly resulted in an increase in lateral branching, contrary to the expected suppression of side shoots. Researchers speculated this might be due to a decreased sensitivity of hemp buds to auxin’s inhibitory effect or a stimulatory effect on the elongation of already formed shoots. However, another study on phytocannabinoid-rich (PCR) Cannabis sativa genotypes (KANADA, FED, and 0.2x-genetic) that had been decapitated showed a different outcome. Here, NAA application significantly reduced total plant height (by 28%) and the length of axillary side-branches (by 58%), creating a more compact growth habit. For the KANADA genotype, this led to a beneficial plant architecture with an inflorescence yield similar to untreated controls, proving advantageous for space-limited indoor cultivation. These contrasting results underscore that the plant’s physiological state (intact versus decapitated) and its specific genotype dramatically influence its response to exogenous auxin application, demanding a tailored approach from growers.

Beyond shaping plant structure, auxins can also contribute to overall yield enhancement by optimising physiological activities. By fostering robust root systems for better nutrient uptake and potentially improving photosynthetic efficiency, auxins lay a strong foundation for vigorous growth and ultimately, a more substantial harvest. Interestingly, studies have shown that while auxins significantly impact plant morphology and yield parameters, their application does not appear to negatively affect cannabinoid content (such as CBD) in the inflorescence or leaves. This is a crucial finding for medicinal cannabis cultivators, suggesting that architectural modifications can be achieved without compromising the desired phytochemical profile.

Auxins

Navigating Auxin Application: Considerations and Nuances

While auxins offer powerful advantages, their effective utilisation in cannabis cultivation demands a nuanced understanding of their behaviour. One of the most critical aspects is concentration dependence. The relationship between auxin concentration and plant growth is not linear but often follows a bell-shaped curve. Low concentrations typically stimulate growth, but exceeding an optimal threshold can lead to inhibitory effects, especially in roots, which are more sensitive to high auxin levels than shoots. Excessively high auxin concentrations can even trigger the production of ethylene, a hormone known to induce premature flowering or senescence, leading to undesirable outcomes. Therefore, precise dosing is paramount to harness their benefits without causing harm.

Another significant factor is genotype specificity. As observed in various studies, different Cannabis sativa genotypes can exhibit distinct responses to identical auxin treatments. The contrasting lateral branching responses to NAA in the MendelNet and Plants 2020 papers serve as a prime example, illustrating that what works optimally for one strain might not for another. This necessitates a trial-and-error approach or careful observation when introducing exogenous auxins to a new cannabis variety. The method and timing of application are equally important; whether auxins are applied as a rooting gel to cuttings or as a foliar spray to growing plants, and at which specific stage of development, will significantly impact the results.

Emerging research into auxin antagonists is opening new frontiers, particularly for in vitro propagation. A novel molecule, α-(2-oxo-2-phenylethyl)-1H-indole-3-acetic acid, or PEO-IAA, acts as a strong anti-auxin. This antagonist disrupts apical dominance, making it a promising tool for increasing shoot multiplication rates in in vitro cannabis cultures. Crucially, recent investigations revealed that the presence of PEO-IAA in culture media did not lead to statistically significant negative changes in cannabinoid gene expression or concentration in certain Cannabis sativa cultivars like ‘USO-31’ and ‘Tatanka Pure CBD’. In fact, ‘Tatanka Pure CBD’ showed a statistically significant increase in CBDA concentration in the presence of PEO-IAA. This discovery holds immense potential for the standardised, large-scale production of medicinal cannabis by improving in vitro multiplication efficiency without compromising the plant’s valuable chemical profile.

Auxins

In conclusion, auxins are indispensable plant hormones that intricately shape the growth and development of Cannabis sativa. From promoting robust root systems crucial for nutrient uptake to influencing stem elongation and branching patterns, their effects are pervasive and profound. Growers who grasp the fundamental roles of auxins and judiciously apply this knowledge can unlock new levels of control over their cultivation. Whether it’s optimising rooting for clones, strategically pruning to manage plant architecture, or leveraging cutting-edge research into auxin antagonists for in vitro propagation, informed auxin management can lead to healthier plants, improved yields, and more consistent harvests. As always, embracing a genotype-specific approach and paying close attention to application rates and timing will be key to successfully integrating these powerful plant growth regulators into your cannabis cultivation regimen. The ongoing exploration of these complex hormonal pathways promises even more refined techniques for the future of cannabis growing.

Resources Below:

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Cannabis & Hemp Seeds: 5 Incredible Benefits for Your Health & Well-being

cannabis & hemp seeds
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From the lush fields of KwaZulu-Natal to the fertile plains of the Western Cape, South Africa is increasingly embracing the idea of cannabis and hemp as a totality. Historically, cannabis in its various forms has carried a heavy weight of stigma, often associated with recreational use. But today, a different narrative is taking root, one that celebrates cannabis and hemp, even embracing the plant in everyday life.  

Much like the broader global trend, South Africa is seeing a growing interest in natural health solutions and diverse, plant-based food options. As our understanding of nutrition evolves, many South Africans are actively seeking out foods that not only nourish but also contribute to overall wellness. This is where cannabis & hemp seeds shine, offering a treasure trove of goodness without any psychoactive effects. Thanks to ongoing research and changing legislation, seeds are emerging as a valuable ingredient, poised to transform our everyday meals into functional foods with incredible health advantages.

1. The Powerhouse of Plant-Based Protein: Fuel for Your Body

In a nation that values hearty meals and strong bodies, the protein content of cannabis & hemp seeds are truly remarkable. These small but mighty seeds pack a serious punch, with whole seeds containing approximately 20-25% protein, and hulled seeds boasting an even more impressive 30-38.7% protein. This makes them a fantastic alternative to traditional protein sources, especially for those embracing plant-based diets or managing allergies.

What sets cannabis & hemp protein apart?

  • Complete Amino Acid Profile: Unlike many other plant proteins that are missing some essential amino acids, cannabis & hemp protein contains all nine that our bodies cannot produce on their own. This makes it a “complete protein,” crucial for muscle repair, growth, and overall bodily function. Think of it as a one-stop shop for your protein needs!
  • Highly Digestible: Research highlights that cannabis & hemp protein is easily digestible, with no natural protease inhibitors (compounds that can hinder protein breakdown) found in the seeds. This means your body can efficiently absorb and utilise this vital nutrient. Studies show digestibility rates of 84-86% for whole seeds and up to 92% for flour.
  • Key Proteins: cannabis & Hemp’s protein magic comes from two main types:
    • Edestin: Making up 60-80% of the total protein, edestin is a high-quality, easily absorbed protein, rich in sulfur-containing amino acids (like methionine and cysteine) that are often limited in other plant proteins.
    • Albumin: Contributing about 25% of the total, albumin complements edestin, offering a well-rounded amino acid profile.
  • Allergy-Friendly & Gluten-Free: For the many South Africans dealing with food sensitivities, cannabis & hemp seeds are a blessing. They are naturally gluten-free and have a very low allergenic profile, making them a safe and inclusive option for individuals with celiac disease or common allergies to soy or wheat.

Beyond basic nutrition, the peptides derived from cannabis & hemp protein also show promise with antioxidant, antihypertensive, antimicrobial, and even neuroprotective properties. These can contribute to managing cardiovascular risks, reducing inflammation, and supporting brain health – truly a protein that does more!

cannabis and hemp seeds

2. The Golden Ratio of Healthy Fats: A Friend to Your Heart

South Africa, like many parts of the world, faces significant challenges with non-communicable diseases, including heart disease. This makes the exceptional fat profile of cannabis & hemp seeds incredibly relevant. Cannabis & Hemp oil, making up 25-35% of the seed (and up to 52.3% in hulled seeds), is a liquid gold with a mild, nutty flavour – and its lovely green hue in cold-pressed form is all-natural, thanks to chlorophyll.

Here’s why cannabis & hemp fats are so special:

  • Rich in Polyunsaturated Fatty Acids (PUFAs): Over 70% of the fatty acids in cannabis & hemp oil are PUFAs, which are essential for many bodily functions and must be obtained from our diet. These include:
    • Linoleic Acid (LA – Omega-6): Essential for healthy skin, cell membranes, and overall growth. It constitutes 51.6-63.7% of hemp oil’s fatty acids.
    • Alpha-Linolenic Acid (ALA – Omega-3): A crucial anti-inflammatory omega-3 fatty acid, important for heart health and brain function. Hemp oil contains a significant 10.5-26.2% ALA.
    • Gamma-Linolenic Acid (GLA) and Stearidonic Acid: These are less common but highly beneficial fatty acids, contributing to hemp’s unique health benefits.
  • The Optimal Omega-6 to Omega-3 Ratio: This is where cannabis & hemp truly shine! With a remarkably balanced ratio of 2.5:1 to 5.5:1 (often cited as an ideal 3:1), cannabis & hemp oil help maintain a healthy inflammatory balance in the body. Many modern diets are skewed towards too much omega-6, which can promote inflammation. Cannabis & Hemp provides these essential fats in perfect harmony, supporting heart health and reducing the risk of chronic inflammatory conditions.
  • Natural Antioxidants: Seeds are rich in tocopherols (Vitamin E), with gamma-tocopherol being the most abundant form. These powerful antioxidants protect your cells from damage and help keep the delicate oils fresh. Think of them as the natural guardians of your well-being.
  • Phytosterols for Cholesterol: These plant compounds, especially beta-sitosterol, are structurally similar to cholesterol and can help reduce its absorption in your gut, contributing to healthy cholesterol levels and cardiovascular health.

To get the most from these delicate fats, opt for cold-pressed hemp oil, which preserves its nutritional quality. It’s best used in uncooked applications like salad dressings (perfect for a fresh South African salad!), dips, or drizzled over steamed veggies or pap. Avoid high heat, as it can damage these beneficial compounds.

3. The Fibre Force: Nurturing Your Gut and Beyond

A healthy gut is the cornerstone of good health, and the seeds are an excellent ally in this regard. These seeds are a fantastic source of dietary fibre, contributing 20-30% of their total carbohydrate content. The majority of this is insoluble dietary fibre, which acts like a broom for your digestive system.

Here’s how cannabis & hemp fibre helps you thrive:

  • Promotes Digestive Regularity: Insoluble fibre adds bulk to your stool, helping food move smoothly through your digestive tract. This aids in preventing constipation and maintaining a healthy, regular bowel rhythm – a common concern for many. The hull of the seed is especially rich in fibre, containing cellulose (46%), lignin (31%), and hemicellulose (22%).
  • Manages Blood Sugar Levels: Fibre plays a crucial role in slowing down the absorption of sugars into the bloodstream. This helps prevent sudden spikes and crashes, making seeds particularly beneficial for individuals managing diabetes or looking to stabilise energy levels throughout the day.
  • Supports Cholesterol Reduction: Dietary fibre can bind to cholesterol in the digestive system, facilitating its excretion and helping to lower overall blood cholesterol levels, further supporting heart health.
  • Aids in Weight Management: Foods rich in fibre promote a feeling of fullness and satiety, which can help control appetite and support healthy weight management goals.
  • Nourishes the Gut Microbiome: While mostly insoluble, some of the fibre in hemp seeds can be fermented by the beneficial bacteria in your gut. This process produces short-chain fatty acids (SCFAs), which are vital for gut health and have systemic benefits for the entire body.

Incorporating whole hemp seeds into your diet – perhaps sprinkled over your morning porridge, a fresh fruit salad, or even mixed into umphokoqo – is a simple yet effective way to boost your fibre intake and support overall digestive wellness.

cannabis an hemp seed

4. Micronutrient Marvels: Vitamins and Minerals for Vibrant Living

Beyond the macronutrients, hemp seeds are a micro-nutrient marvel, brimming with essential vitamins and minerals that are crucial for countless bodily processes and overall vitality.

Vitamins for Life:
Cannabis & hemp seeds provide a noteworthy contribution to your daily vitamin intake:

  • Vitamin E (Tocopherols): A potent antioxidant, Vitamin E protects your cells from oxidative stress. A small serving of hemp seeds or hemp oil can easily meet your daily recommended allowance for this vital vitamin.
  • Vitamins D and A: These fat-soluble vitamins are key for bone health, a robust immune system, and maintaining healthy vision.
  • B-Vitamins (B1 & B9): Cannabis & Hemp seeds contain B1 (thiamine) and B9 (folate), which are essential for energy metabolism, nervous system function, and healthy cell division. These are vital for sustained energy and cognitive health, whether you’re tackling a busy workday or enjoying a hike up Table Mountain.

Minerals for Strength:
Hemp seeds are loaded with a diverse array of essential minerals:

  • Phosphorus, Potassium, Magnesium: These macro-minerals are vital for strong bones, nerve function, muscle contractions, and maintaining electrolyte balance – especially important in our warm climate. Phosphorus is particularly abundant in hulled hemp seeds.
  • Zinc & Copper: Essential for immune function, wound healing, and acting as antioxidants. Zinc, in particular, can provide a significant portion of your daily needs from a single serving.
  • Manganese & Iron: Manganese is crucial for bone development and metabolism, while iron is fundamental for oxygen transport in the blood, combating fatigue and supporting overall energy levels.
  • Calcium: Important for skeletal strength and numerous cellular processes.

While these minerals are generally quite stable, consuming hemp seeds in their minimally processed forms helps ensure you get the full spectrum of benefits. Although natural compounds like phytates can sometimes affect mineral absorption, traditional methods like fermentation (used in some food products) can help reduce these, enhancing the seeds’ overall bioavailability.

cannabis and hemp seeds

5. Bioactive Boosters: Unlocking Nature’s Therapeutic Potential

Cannabis & Hemp seeds are more than just a collection of basic nutrients; they are also a rich source of fascinating bioactive compounds – natural chemicals that offer therapeutic benefits beyond standard nutrition. These secondary metabolites work synergistically, contributing to overall well-being.

  • Terpenes: The Scent of Health: These aromatic compounds give cannabis & hemp its distinct flavour and scent. Over 85 volatile terpenes have been identified in cannabis & hemp seed oil, including beta-myrcene, D-limonene, and beta-caryophyllene.
    • Antioxidant & Anti-inflammatory: Terpenes actively protect cells from damage and help reduce inflammation, offering relief for conditions like osteoarthritis.
    • Metabolic & Mood Support: Beta-caryophyllene, for example, has been linked to improving insulin sensitivity and regulating cholesterol. Other terpenes can contribute to balancing mood, reducing tension, and even supporting better sleep and anxiety management – a welcome boost in our fast-paced lives.
  • Flavonoids: Nature’s Protectors: These powerful phenolic compounds are abundant in seeds, particularly in the hull. They are renowned for their wide-ranging health benefits:
    • Antioxidant & Anti-inflammatory: Flavonoids are formidable protectors against cellular damage and chronic inflammation.
    • Neuroprotective & Cardiovascular: They play a role in brain health, potentially offering protection against neurodegenerative diseases. Some flavonoids can also help regulate blood pressure by influencing nitric oxide levels, benefiting your heart.
  • Carotenoids: Vision Protectors: Seeds also contain carotenoids like lutein and zeaxanthin, which are essential for eye health. These compounds accumulate in the macular region of the eye, protecting against light-induced damage and reducing the risk of age-related macular degeneration.
  • Phytocannabinoids: Trace Amounts, Emerging Interest: It is crucial to understand that seeds contain only trace amounts of phytocannabinoids like Cannabidiol (CBD) and Tetrahydrocannabinol (THC). Industrial hemp is specifically bred to ensure THC levels are well below legal thresholds (e.g., 0.2-0.3%), meaning hemp seeds are non-psychoactive and entirely safe for consumption. While not a primary source of high-concentration cannabinoids, the minuscule amounts, particularly CBD, are being studied for their potential therapeutic benefits in managing pain and supporting neurological health. Any higher levels would typically be from external contamination of sticky resin during harvest, which is addressed through proper cleaning and processing. For food purposes, rest assured that hemp seeds are purely for their nutritional value, not for recreational effects.

These bioactive compounds highlight how hemp seeds offer a holistic approach to wellness, tapping into nature’s intricate chemistry to support various bodily systems.

cannabis and hemp seeds

Bringing Hemp Seeds to the South African Table

The versatility of cannabis & hemp seeds means they can easily become a staple in the South African diet, enriching our local cuisine with their incredible benefits.

  • Culinary Delights: Sprinkle shelled hemp seeds over your morning mieliepap, add them to smoothies with local fruits like mango and pawpaw, or stir them into yoghurts. They make a fantastic crunchy topping for salads, roasted vegetables, or even chakalaka.
  • Baking & Beyond: Cannabis & Hemp flour can be a nutritious addition to your baking, whether you’re making gluten-free bread, muffins, rusks, or even vetkoek. Hemp protein powder can boost your post-workout shakes or energy bars.
  • Hemp Milk: A creamy, plant-based milk alternative that’s perfect for those with lactose intolerance or simply seeking a healthier option. It can be used in teas, coffees, or poured over cereals.
  • Hemp Oil: Drizzle cold-pressed hemp oil over a grilled braai salad or use it to make a vibrant vinaigrette.

As the market for natural and functional foods grows in South Africa, brands are increasingly exploring hemp-based products. Look for trusted local and international brands that offer shelled hemp seeds, hemp oil, hemp flour, and protein powders.

Embrace the Future of Food with Hemp

Cannabis & Hemp seeds are truly a gift from nature, perfectly aligned with our modern quest for holistic health and sustainable living. Their remarkable blend of digestible protein, heart-healthy fats, vital fibre, essential vitamins and minerals, and powerful bioactive compounds makes them an unparalleled superfood.

In South Africa, where we cherish both our traditions and our forward-thinking spirit, seeds offer an exciting opportunity. They represent a bridge between ancient wisdom and modern nutritional science, promising a path to enhanced well-being for individuals and a more sustainable food system for our nation.