Organic Cannabis Growing: Living Soil and Natural Methods

Organic cannabis growing takes a fundamentally different approach from conventional cultivation with mineral fertilisers: instead of feeding the plant directly, you feed the soil. A living, microbially active substrate – Living Soil – supplies the plant with everything it needs through complex biological networks. The result is flowers with a more complex terpene profile, more intense flavour, and a cleaner smoking experience. For Cannabis Social Clubs that value quality and sustainability, organic growing is an excellent choice.

## The Living Soil Concept: Soil as an Ecosystem

Living Soil is not a product but a concept. It describes a substrate that hosts a complete microbial ecosystem – bacteria, fungi, protozoa, nematodes, and microarthropods work together in a complex network known as the Soil Food Web.

In healthy Living Soil, the following occurs: bacteria decompose organic matter and make nutrients plant-available. Mycorrhizal fungi form symbiosis with plant roots and extend their nutrient uptake range by 10 to 100 times. Protozoa and nematodes eat bacteria and excrete plant-available nutrients – a process called mineralisation. Fungal hyphae form an underground network (mycelium) that can transport nutrients and even signalling compounds between plants.

The crucial advantage: the plant self-regulates which nutrients it absorbs, when, and in what quantity. It does this by releasing sugars and other exudates into the soil through its roots, attracting and feeding specific microorganisms. These microorganisms provide the required nutrients in return. This system is self-regulating, largely eliminating the need for pH corrections and EC measurements.

The concept was popularised primarily by soil ecologist Dr. Elaine Ingham (Soil Food Web School) and cannabis pioneer Jeff Lowenfels (Teaming with Microbes).

## Compost Teas: Liquid Life for the Soil

Actively Aerated Compost Teas (AACT) are one of the most powerful tools in organic growing. They exponentially multiply the beneficial microorganisms from compost and deliver them in liquid form to the soil or as foliar spray to the plants.

**Making a Simple Compost Tea:** You need a bucket (20 L), an aquarium pump with air stones, high-quality worm castings or compost (approximately 500 g per 20 L), a food source for the microbes (1–2 tablespoons unsulphured molasses for bacteria or oat flour for fungi), and chlorine-free water (let tap water stand for 24 hours or use a carbon filter). The tea is aerated for 24–36 hours, then used immediately – it only remains viable for a few hours, as microorganisms die without aeration.

**Bacteria-Dominant Tea:** Molasses as a food source promotes bacterial multiplication. Bacteria are particularly important during the vegetative phase, as they fix nitrogen and make it plant-available.

**Fungi-Dominant Tea:** Oat flour, fish hydrolysate, or humic acids promote fungal growth. Fungi dominate during the flowering phase and are crucial for phosphorus and trace element transport.

**Application:** As a soil drench: pour undiluted directly onto the soil, ideally in the morning. As a foliar spray: dilute 1:5 and spray onto leaf undersides in the early morning or with lights off. The foliar spray colonises the leaf surface with beneficial microbes (phyllosphere), which outcompete pathogenic fungi and bacteria.

## Mycorrhizae: The Underground Internet

Mycorrhizal fungi (particularly arbuscular mycorrhizae – AM) are the most important symbionts in organic cannabis growing. They penetrate the outer cells of plant roots and form tree-like structures (arbuscules) through which nutrient exchange occurs.

**What Mycorrhizae Do for Cannabis:** Fungal hyphae extend the effective root volume by 10 to 100 times – nutrients and water from soil areas that roots alone could not reach become accessible. Phosphorus uptake is dramatically improved – phosphorus being a poorly mobile nutrient. Mycorrhizae protect roots from pathogenic fungi (e.g., Pythium, Fusarium) through physical barriers and signalling compounds. They improve drought resistance and increase tolerance to salt stress.

**Application:** Mycorrhizal inoculum (Glomus intraradices and other species) should be brought directly to the roots – best sprinkled into the planting hole when transplanting or dusted onto roots before planting. Later application via irrigation water is less effective. Important: high concentrations of phosphorus fertiliser inhibit mycorrhizal colonisation – not a problem with Living Soil, where phosphorus is released slowly and organically.

## Worm Castings: The Gardener's Black Gold

Worm castings (vermicompost) are the most nutrient-rich and microbially active natural substrate available. They are produced through the digestion of organic waste by composting worms (Eisenia fetida – red wigglers).

**Properties:** Contains all macro- and micronutrients in plant-available form. Rich in humic and fulvic acids that improve nutrient uptake. Contains billions of beneficial microorganisms per gram. Excellent water-holding capacity with good drainage. Promotes formation of stable soil aggregates. Contains natural growth hormones (auxins, cytokinins) and enzymes.

**Home Production:** A worm bin can be started with approximately 500 g of red wigglers. They are fed kitchen scraps, cardboard, and newspaper. A well-maintained worm compost produces several kilograms of high-quality castings monthly. For a Cannabis Social Club, a larger continuous flow-through system can scale production.

**Use in Cannabis Growing:** 20–30% proportion in the substrate mix. As top dressing: apply a 1–2 cm layer on existing soil. As a base for compost teas. Combined with mycorrhizae and bacterial preparations as a bioactive soil inoculant.

## Natural Pest Control: Beneficial Insects and Biological Methods

In organic growing, synthetic pesticides are replaced by biological pest management (Integrated Pest Management – IPM). The basic principle: prevention is better than cure, and biological agents do not harm the soil ecosystem.

**Beneficial Insects:** Predatory mites (Amblyseius californicus, Amblyseius swirskii) are the most important beneficial organisms in cannabis growing. A. californicus specialises in spider mites – the most common and dangerous pest in indoor growing. A. swirskii is a generalist that feeds on thrips, whiteflies, and young spider mites. Preventive deployment every 2–4 weeks is more effective than reactive deployment during infestations. Lacewings (Chrysoperla carnea) are voracious predators in the larval stage, consuming aphids, thrips, spider mites, and mealybugs. A single lacewing larva can consume up to 500 aphids during its development. Hypoaspis mites (Stratiolaelaps scimitus) live in the soil and feed on fungus gnat larvae, springtails, and other soil organisms. Parasitic wasps (Encarsia formosa, Aphidius colemani) lay eggs inside pests – the larvae consume the host from within. Highly effective against whiteflies and aphids.

**Neem Oil:** Neem oil (from the seeds of the neem tree, Azadirachta indica) contains azadirachtin, a natural insect growth regulator. It disrupts insect larval moulting, acts as a feeding deterrent, and has repellent effects. Application: 3–5 ml neem oil per litre of warm water with a drop of dish soap as emulsifier. Apply as foliar spray every 7–10 days. Do not spray directly on flowers during the flowering phase – neem oil can affect taste. Alternatively, use as a soil drench where the active ingredient is absorbed systemically through the roots.

**Potassium Soap (Insecticidal Soap):** Dissolves the waxy layer of soft-bodied insects (aphids, whiteflies, spider mites), causing dehydration. 10–20 ml potassium soap per litre of water, spray directly onto pests. No residue problems, biodegradable.

**Bacillus thuringiensis (Bt):** A naturally occurring soil bacterium that produces toxins specifically killing caterpillars and certain larvae without harming beneficial insects. Bt var. israelensis (Bti) is highly effective against fungus gnat larvae. Apply as an irrigation water additive.

## Companion Planting: Natural Plant Communities

Companion planting – the deliberate planting of companion plants alongside cannabis – uses natural plant interactions for pest deterrence, soil improvement, and pollinator attraction.

**Basil:** Repels thrips, flies, and mosquitoes through essential oils (linalool, eugenol). Linalool is also a cannabis terpene, suggesting synergistic effects. Basil planted directly beside cannabis can increase terpene diversity in the grow room.

**Lavender:** Repels moths, fleas, and mosquitoes. Attracts pollinating insects that also draw other beneficial insects into the garden. Useful indoors as a potted plant beside the growing area.

**Calendula (Marigold):** Attracts aphids and diverts them from cannabis (sacrificial plants). Their roots excrete substances that repel nematodes. Particularly valuable in outdoor growing.

**Clover (Trifolium):** As ground cover between cannabis plants, clover fixes atmospheric nitrogen via root nodule bacteria (rhizobia). This nitrogen gradually becomes available to cannabis as the clover dies back or is mulched. Protects soil from drying and erosion.

**Garlic and Onions:** Their sulphur-containing compounds repel many insects and can also prevent fungal diseases. Garlic extract spray is a proven remedy against spider mites.

## Super Soil Recipes: The Perfect Mix

Super Soil is a pre-mixed and composted soil containing all nutrients cannabis needs from seedling to harvest – without additional fertilisation. The concept was popularised by American cannabis breeder Subcool.

**Classic Super Soil Recipe (for approximately 100 L):** Base: 30 L high-quality potting soil (peat-free). 15 L worm castings. 10 L perlite (for drainage). 10 L compost (well-aged garden compost). 5 L coco coir. Mineral amendments: 500 g basalt rock dust (trace elements, silicon). 500 g bone meal (phosphorus, calcium). 250 g blood meal (nitrogen). 250 g kelp/seaweed powder (potassium, growth hormones). 250 g dolomite lime (calcium, magnesium, pH buffer). 150 g bat guano (phosphorus). Biological amendments: 50 g mycorrhizal inoculum. 50 g Azomit (volcanic rock dust with over 70 minerals).

**Preparation:** Mix all dry ingredients thoroughly. Moisten with water (damp, not wet – the moisture of a wrung-out sponge). Fill into a large container or bin liner and close loosely – the soil must be able to breathe. Let it "cook" (compost) for at least 4–6 weeks. Microorganisms break down the organic amendments, making nutrients plant-available. Turn regularly and lightly re-moisten as needed.

**Application:** Fill the bottom half of the pot with Super Soil, the top half with a lighter mix (base without the amendments). Roots grow into the Super Soil and find nutrients when they need them. Water only with plain water – no additional fertilisers needed.

## No-Till Method: Never Dig, Never Replace

The no-till method is the most consistent form of organic growing. After harvest, the soil is not replaced or tilled but regenerated and reused through top dressing and mulching – for years on end.

**Principle:** Soil is an ecosystem that improves with every season. Tilling destroys the fungal networks (mycelium) that have built up over months. No-till preserves these structures and allows the soil to become more nutrient-rich and microbially active harvest after harvest.

**Practice:** After harvest: leave stems and roots of the old plant in the soil – they are decomposed by microorganisms and recycled into nutrients. Apply top dressing: a layer of worm castings, compost, bone meal, and kelp on the soil surface. Apply mulch layer: straw, chopped clover, or rice hull dust. Mulch protects soil from drying, regulates temperature, and provides habitat for soil organisms. Water regularly with compost tea to promote microbial activity. Plant new seedling – the cycle begins again.

**Advantages of the No-Till Method:** No substrate costs after initial setup. Increasing soil quality with every season. Lower workload (no mixing, no pH measuring, no EC measuring). Natural pest management through established beneficial populations in the soil. More complex terpene profile – many experienced growers report significantly better flavour with no-till growing.

## Benefits for the Terpene Profile

One of the most frequently cited advantages of organic growing is the superior terpene profile. Terpenes are the aromatic compounds that give cannabis its characteristic aroma and modulate effects through the entourage effect.

**Why Organic Growing Produces Better Terpenes:** Mycorrhizal fungi demonstrably promote terpene and flavonoid production – likely as part of plant-fungus communication. A microbially active soil delivers nutrients in a natural, slow, and balanced form – without the stress peaks that synthetic fertilisers can cause through salt accumulation. The slower but steadier nutrient supply allows the plant to invest more energy in secondary metabolite production (terpenes, flavonoids) rather than rapid vegetative growth. Organic substances such as humic and fulvic acids improve nutrient uptake and can directly stimulate terpene production. The absence of synthetic chemicals eliminates the possibility of chemical residues that could impair flavour during consumption.

Studies from the University of Vermont and reports from the commercial cannabis industry in the US (particularly from Oregon and Northern California) show that organically grown cannabis consistently exhibits higher terpene concentrations and greater terpene diversity than conventionally grown cannabis. Strains like Sour Diesel, OG Kush, and Gelato show 30–50% higher total terpene concentrations in Living Soil cultivation.

For Cannabis Social Clubs that want to offer their members the best possible product, organic growing with Living Soil is an investment in quality, sustainability, and flavour. The initial setup requires more knowledge and planning, but ongoing effort is lower and results are convincing when implemented correctly.