Short answer. Living soil is a large volume of compost-rich, amended soil that you reuse without tilling and water with plain, dechlorinated water. Soil microbes and invertebrates mineralise organic matter into plant-available nutrients. Done well, it needs little more than water, mulch and a top-dress between runs. Don't pH-adjust aggressively, don't add salt fertilisers, and don't sanitise it. The evidence base is mostly Grower practice: soil-health principles from agronomy are well established [1], but controlled cannabis comparisons of living soil vs other systems are scarce.
How it works
- Nutrients come from organic amendments (compost, worm castings, seed meals, rock dusts, kelp, bone/fish meal) released by biology. Release speed depends on moisture, temperature and organism activity, so it lags by days to weeks.
- pH is buffered by organic matter and carbonates; plants and microbes work around a near-neutral pH. Jardin leaves living-soil pH uncontrolled at ~6.3–7.0 [4].
- No-till keeps fungal networks and soil structure intact between runs; a mulch layer and optionally a cover crop keep the surface moist and alive (directly echoing NRCS principles: minimise disturbance, keep soil covered, keep living roots, maximise diversity [1]).
Numbers that matter
| Parameter | Target | Notes |
|---|---|---|
| Container volume | ≥ 50–100 L (15–25 US gal) per plant, or beds | Small pots lack buffering; Grower practice |
| Water | Dechlorinated (stand 24 h or carbon filter for chloramine) | pH as-is unless very alkaline |
| Soil moisture | Evenly moist; never dry, never saturated | Jardin uses VWC + soil temperature, dosing disabled [4] |
| Soil temperature | 18–24 °C (64–75 °F) | Biology slows below ~15 °C |
| Mulch | 3–5 cm (1–2 in) straw, leaves or living cover | |
| Top-dress | Between runs and mid-veg; weeks before need | Organic N release is slow |
How to run it
- Build (or buy) a mix of roughly equal parts aeration (pumice/perlite), compost/castings and peat or coco, plus a balanced amendment package. Let it "cook" moist and warm for 2–4 weeks.
- Plant directly; water gently; mulch.
- Water by weight or VWC; living soil wants steady moisture.
- Feed the soil, not the plant: top-dress amendments and water in; compost teas or extracts by hand if you use them.
- Between runs: cut stems at soil level, leave roots, top-dress, re-mulch, replant.
Fixing problems
- Diagnose before amending: in living soil, pH or water problems and cold soil cause most "deficiencies".
- Fast-acting organic inputs (fish hydrolysate, kelp extract, a light foliar) bridge a gap while a top-dress breaks down.
- Pests: fungus gnats love moist mulch; use sticky traps and predatory mites or Bacillus thuringiensis israelensis rather than drying the soil out.
Jardin notes
Jardin medium "Living soil": dosing disabled in software, EC targets hidden; Jardin runs moisture, climate, photos and IPM monitoring. Time-to-harm on pump failure: days. Automation level 3 for water [4].
Common mistakes
- Flushing living soil before harvest. There's nothing to flush, and pre-harvest flushing is a Myth that costs yield and resin. Keep watering normally (see the flush debate).
- Small pots of "living soil" fed like hydro.
- Chlorinated or hydrogen-peroxide water, or sanitisers poured on the bed.
- pH-ing water to 6.0 out of habit.
- Over-amending (hot soil) and burning seedlings.
Evidence
Soil-health principles are Established agronomy [1]. Organic feeding can produce high cannabis yields when N supply is adequate (~389 mg N/L liquid organic feed maximised veg yield in coir-based organic media [2]). Claims specific to living soil (better terpenes, "cleaner" smoke, microbial-driven quality) are Grower practice with no controlled cannabis data we can cite.
Living soil is an organic growing medium managed to sustain an active soil food web, so microbes and invertebrates release nutrients and the soil is reused across cycles.Super soil is a heavily amended organic soil mix, rich in compost and slow-release amendments, intended to feed a plant through most of its life with only water.Top dressing is spreading dry fertiliser or amendments on the soil surface, usually under mulch, so nutrients release into the root zone as the plant is watered.An organic fertiliser supplies nutrients from plant, animal or mineral-rock sources that soil microbes must break down into ions before roots can absorb them.pH measures how acidic or alkaline a solution is on a 0–14 scale; in growing it controls nutrient uptake, with soil best near 6.0–7.0 and hydro 5.5–6.5.A carbon filter scrubs odour from exhaust air by passing it through activated carbon, which adsorbs aroma compounds such as terpenes.Compost tea is a liquid made by steeping compost or worm castings in water, often aerated with food sources, to extract and multiply microbes for the root zone.A nutrient deficiency is a shortage of an essential element in the plant tissue, causing characteristic symptoms; the cause is often pH or uptake rather than an empty feed.Small dark flies of the genus Bradysia (family Sciaridae) whose larvae live in wet growing media, feeding on fungi, organic matter and young roots.A coloured card coated in non-drying glue that catches flying insects, used mainly to monitor pest trends: yellow for gnats, whiteflies and aphids, blue for thrips.Mites, mostly of the family Phytoseiidae, released as biological control to eat pest mites, thrips larvae, whitefly eggs or fungus gnat larvae.Bacillus thuringiensis subsp. israelensis, a bacterial strain whose toxins kill fly larvae, including fungus gnats, after ingestion; applied as a medium drench.EC (electrical conductivity) measures how well a solution conducts electricity, a proxy for total dissolved salts; growers read it in mS/cm to gauge nutrient strength.Integrated pest management: preventing and controlling pests by combining monitoring, prevention, cultural, biological and, as a last resort, chemical tools against set action thresholds.Feeding only plain water for days or weeks before harvest to "clean" the plant; GenetixBay rates it a Myth that harms yield, unlike a root-zone salt flush.Terpenes are volatile hydrocarbon compounds built from five-carbon isoprene units; in cannabis they are made in the trichome heads and are a major part of aroma and flavour.
