One school of cannabis growing holds that once your soil is built correctly, you never feed the plant again: you feed the soil, and the soil feeds the plant. It is a coherent method with real results behind it, and it is not a claim that every other approach is wrong. This article sets out what it is, what it demands, and where it fits alongside the way most growers actually work.
A note on framing. This series covers True Living Organics (TLO) as one school among several. It is not a criticism of mineral or liquid nutrient programmes, which are well understood, highly reproducible and what most commercial and most home growers use. That includes growing under GACP conditions, where documented, repeatable inputs are a requirement rather than a preference. For that approach, see the forum topics on mineral nutrient programmes and nutrient deficiencies (topics 1082 and 1100) and the General Nutrients category (268). For a broader comparison of living soil, no-till and synthetic feeding, see topic 1091, Organic vs Synthetic: Living Soil & No-Till. Read this as a different set of trade-offs, not a verdict.
Source. The method is set out in the book True Living Organics by the author who writes as “The Rev” (Green Candy Press; first published 2012, second, expanded edition 2016). Sections 1 to 4 summarise what the book says. Section 5 onward is commentary. Specific figures can differ between editions, so check them against the edition you own.
1. The Core Claim
TLO’s founding idea is simple to state and hard to carry out: build a soil that contains everything the plant will need for the whole cycle, fill it with a large and diverse microbial community, and then add nothing but plain water.
The Rev calls this “water-only growing.” The reasoning behind his ban on liquid feeding is the part worth understanding, because it is not arbitrary.
The book holds that chelated synthetic nutrients, and liquid feeds generally, disrupt the soil microbial community. In this model, those fungi, bacteria, protozoa and nematodes do the actual work of turning organic amendments into nutrients the plant can use. According to TLO, only two liquids should ever touch the soil: pure water, and TLO tea.
Section 5 asks whether that disruption is as complete as the method claims. What matters first is the logic: if your nutrient delivery system is the microbial community, anything that damages it damages your feeding programme.
2. What Replaces Feeding
If you are not feeding, four things have to do the work instead. Each has its own article in this series.
A heavily amended soil mix. This is not potting soil with a bit of compost. It is a purpose-built medium containing slow-release organic amendments in set proportions. The series articles on dry organic nitrogen sources and on slow-release minerals for living soil cover what goes in and why.
Core feeding and layering. You cannot mix enough nitrogen and phosphorus into the soil at the start without harming the microbes. So TLO puts concentrated amendments in separate pockets that the roots grow into later: vertical holes near the pot wall, plus thin layers at the bottom and top of the pot. The series article on core feeding and layering covers the technique.
Teas. These are aerated compost or worm-casting brews, applied only a few times per cycle. The series article on TLO teas covers the recipes and, importantly, what the agricultural science says about them.
Soil recycling. Instead of throwing away used soil, TLO breaks down the root ball and re-amends it, so the same soil is used for years. The series article on recycling living soil gives the full recipe.
3. The Rules That Follow
These are the method’s operating rules as the book states them.
| Rule | Reason given |
|---|---|
| No liquid fertiliser of any kind, including organic liquids | Chelating acids and high soluble concentrations disrupt the microbial community |
| Never high-phosphorus liquid feeds | These specifically suppress mycorrhizal fungi |
| No chlorinated water | Held to kill soil microbes (see section 5: this needs qualification) |
| Mycorrhizal inoculant once, at transplant | The method holds that one inoculation is enough because the fungi persist once established on roots. Evidence on repeat dosing in containers is limited |
| Amendments must be cured into the mix before roots reach them | Raw organic material heats up, acidifies and damages roots |
| Bigger pot = less intervention | Under a 400 W HID, the book gives 3.5 gal (≈13.25 L) as the size at which layering and core feeding alone allow genuine water-only growing |
That last row is the most practically useful rule in the whole method. The smaller the pot relative to the plant, the more intervention the method requires. In a 2 gal (≈7.5 L) pot, The Rev uses core feeding plus two or three teas. A 3 gal (≈11.4 L) pot sits in between and needs less help than 2 gal, but it is still below the threshold. Only at 3.5 gal (≈13.25 L) or larger does the book treat water-only growing, with no teas, as realistic under a 400 W HID. If you want to grow water-only, the cheapest way to get there is a bigger pot.
4. The Timescale Nobody Mentions First
TLO is not a system you can switch to mid-cycle.
Soil must be cured before use. That means mixing and moistening the amendments, then turning them every few days for two to four weeks, at a temperature of at least 15.5 °C, and longer if it is cooler. The Rev routinely cures for 30 days and notes that under-cured soil produces sick plants. In a cold garage, expect the full month. In Thai temperatures, expect it to go faster, but do not assume you can skip it.
Recycled soil needs the same treatment. The recycle mix is cured for roughly 30 days, or about two weeks if the tumbler sits in full sun.
And the microbial community takes time to settle. The book explicitly asks the grower not to panic and switch back to liquid feeding while that is happening.
So the honest entry cost is a month of preparation before you plant anything, plus the amendment shopping list, plus space to cure and store soil. That is the real barrier, not the technique.
5. Where the Evidence Needs a Qualification
The book states two of its basic claims more absolutely than the agricultural evidence supports. The articles in this series qualify those claims rather than repeat them.
Chlorinated tap water. The claim that chlorinated water kills your soil biology is much stronger than the evidence supports. Drinking water carries little chlorine. The WHO-based minimum is about 0.2 mg/L (ppm) of free chlorine at the tap, and Thai waterworks report working to that floor. One Thai study of a Bangkok distribution network measured about 0.2 to 1.0 mg/L where water enters the network and 0.05 to 0.6 mg/L at the farthest point. Chlorine binds to clay and organic matter, which reduces its effect on microbes. Colorado State University Extension describes a study (not named in its summary) in which highly chlorinated water was applied to soil continuously for 126 days. Microbial populations at all depths were back to pre-treatment levels two days after the treatment stopped. The same source reports that in one study, water at around 65 ppm chlorine was needed to kill soil microorganisms down to about 15 cm (6 in). That is far above any drinking-water level. These figures come from extension summaries, not from a primary paper we could check, so treat them as indicative. The series article on water for living soil covers this properly, including the part the book gets right: chloramine, unlike chlorine, does not escape into the air if you leave the water standing.
Aerated compost tea. The scientific evidence for compost tea is much weaker than cannabis-growing literature suggests. Sugar-fed aerated brews also raise a genuine food-safety concern. The series article on TLO teas covers both the recipes and the evidence, because a grower deserves the second as well as the first.
Neither qualification invalidates the method. Growers get excellent results with TLO, and its soil-building half rests on well-established soil science. But repeating every claim uncritically would make this less useful than separating what is soil science from what is practitioner tradition, and the articles in this series keep that separation throughout.
6. Who This Suits
Good fit: growers running a perpetual harvest in a stable indoor space; people who want to stop buying bottled nutrients and will buy amendments in bulk instead; anyone with room to cure and store soil; growers who enjoy the process as much as the outcome.
Poor fit: anyone who needs a documented, repeatable input record for every batch. That includes anyone working towards GACP or GMP, where the series article on what GMP actually means explains why input records are the whole point. It also includes growers with a single tent and no storage, and anyone who needs to fix a problem quickly mid-flower, because a living-soil system is deliberately slow to respond.
And a tropical caveat: the book was written for temperate indoor growing, and its curing temperatures reflect that. Curing times, watering frequency, worm-bin moisture and fungus gnat pressure all behave differently at 30 °C and 80% humidity. Each article in this series points out where the adaptation matters.
7. The Series at a Glance
This article is the starting point for the series. The companion articles cover:
- Dry organic nitrogen sources
- Slow-release minerals for living soil
- Core feeding and layering
- TLO teas: recipes and evidence
- Recycling living soil
- Water for living soil
- What GMP actually means
For the wider organic-versus-synthetic comparison, see topic 1091. For mineral feeding and deficiency diagnosis, see topics 1082 and 1100 and the General Nutrients category (268).
If you run living soil in Thailand under a licence, or use these methods for other legal crops elsewhere in the region: what did you have to change from the book? Curing time, amendment sourcing, moisture management, pest pressure. The tropical adaptation of this method is not written down anywhere, and this community could write it.
This article is part of the Asiannabis Community educational series on cultivation. It describes one growing method among several and is general information. Cultivation in Thailand is subject to licensing, and cannabis flower is a controlled herb under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568. No fertiliser regime, living-soil or mineral, is a substitute for compliance with GACP input records.