Indigenous Microorganisms — IMO — is the most powerful soil inoculant in the Korean Natural Farming repertoire and the most misunderstood. Master Cho's premise here is that the microbial community already living in a healthy patch of forest near your property is better suited to your soil than any commercial inoculant could be — the microbes are climate-adapted, locally evolved, and accustomed to the same temperature swings, humidity, and rainfall patterns the property experiences. The job is not to import biology. The job is to collect, multiply, and redistribute biology that is already thriving within a quarter-mile of where you stand.
IMO is a four-stage succession. Each stage builds on the previous one, with a specific purpose: IMO-1 collects, IMO-2 stabilizes, IMO-3 matures, IMO-4 marries the captured community to your property's soil. Done properly, the final product is a living soil amendment that can be applied at scale, stored for months, and used to accelerate decomposition in compost piles, suppress soil-borne disease, and rebuild biology in degraded ground.
What you're actually capturing.
The white fuzz that grows on the rice during IMO-1 is dominated by aerobic fungi and bacteria native to that specific forest understory — species adapted to the leaf litter, the soil pH, the seasonal cycles, the relationship with the trees overhead. In the Hill Country, that means microbes that have evolved alongside live oak, juniper, and mesquite; that tolerate alkaline soils; that survive August heat; that are already in symbiosis with the mycorrhizal networks of mature trees. That community cannot be replicated by a lab in another state.
This is why IMO outperforms imported commercial inoculants on real property work. The biology is pre-adapted to the conditions it will be released into.
Stage 1 — the capture.
- Cook 2 cups of plain white rice — al dente, slightly undercooked, no salt or oil. Let it cool to room temperature.
- Build a small cedar box. 8″ × 6″ × 4″ deep, no lid. Untreated wood only — cedar, pine, or oak. The wood breathes; that's part of the system. Or use a wooden lemon crate.
- Fill the box loosely with cooked rice. Don't pack it down. Loose rice has more surface area for microbes to colonize.
- Cover the top with paper towel secured by a rubber band. This keeps insects and rodents out while letting microbes in.
- Find a healthy forest understory within a quarter-mile of your property. Mature live oak with thick leaf duff is ideal in the Hill Country. Look for ground that hasn't been disturbed; if there's visible white mycelium under the leaves, that's the spot.
- Bury the box partially in the leaf litter, paper-towel side up. Cover with a layer of leaves, then a flat stone or piece of bark to weigh it down. Leave for 48-72 hours, depending on humidity. Higher humidity = faster colonization.
- Retrieve when the rice is covered in white mycelium. The color matters: white = success. Pink/red = wild yeast (still usable, less common). Black or green = mold contamination; throw out and try again at a different site. The smell should be sweet, earthy, fermented bread — not putrid.
The best IMO-1 captures we've done at Johnson Ranch came from mature live oak groves with at least 4 inches of leaf litter accumulation. Avoid roadsides, anywhere with herbicide history, and pasture edges — commercial agriculture downwind affects forest-floor microbial diversity. State parks and protected greenways are excellent if you can lawfully collect at the surface.
Stage 2 — the stabilization.
IMO-1 is alive and fast-degrading. Within a week it will go anaerobic and rot. IMO-2 freezes the community in time by encasing it in brown sugar — the same osmosis principle as FPJ.
- Weigh the IMO-1 rice. Measure out an equal weight of unsulphured brown sugar. (1 lb rice = 1 lb sugar.)
- Mix rice and sugar thoroughly in a large glass jar or food-grade plastic bucket. Break up the rice clumps; coat every grain in sugar.
- Pack to 2/3 of jar height. Leave headspace for fermentation gas. Cover with paper towel + rubber band — not airtight.
- Store in cool, dark place 7 days. The sugar will draw moisture out of the rice osmotically; liquid will pool at the bottom; the smell turns from fresh-bread to sweet-fermented — like sake or wine. That's the LABs and yeasts metabolizing the sugar while the fungi go dormant in solution.
- At day 7, drain the liquid. The amber-brown liquid is finished IMO-2. Store in glass at room temperature, capped loosely. Shelf-stable for one year if stored cool and dark.
Stage 3 — the maturation.
IMO-3 wakes the IMO-2 microbes and grows them out on wheat bran — the substrate that gives them surface area to multiply and the carbohydrate to fuel rapid reproduction. The output is a granular, brown, faintly-fermented soil amendment.
- Take 1 cup IMO-2 and dilute with 10 gallons dechlorinated water. Add 1 cup of dechlorinated water + 1 tbsp brown sugar to re-activate the microbes. Let sit 30 minutes; you should see slight bubbling.
- Mix the dilution into 50 lb of wheat bran — available at feed stores ($20/50 lb) or as standard horse-and-livestock supplement. Wet the bran to roughly 60% moisture — squeeze a handful; it should hold shape but no water should drip out.
- Pile the wetted bran in a wooden box or on a tarp under shade. Pile depth 12-18 inches. The pile must breathe; don't compact.
- Within 24-48 hours the pile will heat to 130-140°F — that's the aerobic microbes consuming sugar and reproducing rapidly. Check temperature with a compost thermometer.
- When pile temperature drops below 95°F (around day 5-7), the carbon is consumed. The bran is now coated with mature microbial colonies. That's IMO-3. Air-dry to under 30% moisture for storage; bag in burlap or cloth (not plastic — it needs to breathe).
Stage 4 — the marriage to your soil.
IMO-4 is the final stage. You take the matured bran community and mix it with native soil from your own property in equal parts. The microbes from the forest meet the microbes from your ground; the combined community is what you actually apply to beds and pastures.
- Collect topsoil from your property — the top 4 inches from a healthy spot, ideally under existing tree canopy. Sift to remove rocks and larger debris.
- Mix IMO-3 with your topsoil 1:1 by volume. Add water to reach 50-60% moisture (same squeeze test).
- Pile in a shaded spot, cover loosely with breathable cloth or burlap. The mix should run 95-110°F for 5-7 days — cooler than IMO-3 because there's less sugar.
- When temperature settles to ambient, the community has integrated with the local soil organisms. That's finished IMO-4. Store dry in burlap; shelf life 6 months.
How to apply.
IMO-4 is the form you'll use most. The earlier stages are inputs to make more IMO-4.
- Compost-pile accelerator — mix 1 cup IMO-4 per cubic foot of compost. Cuts decomposition time roughly in half.
- Bed inoculation — 1 lb IMO-4 per 100 sq ft, scratched into the top 2 inches of bed before planting.
- Pasture broadcast — 5 lb per 1000 sq ft, broadcast with seed at fall overseed.
- Tree planting — 1 handful in the bottom of the planting hole, before the root ball goes in.
- Liquid form — 1 cup IMO-2 (the preserved liquid) in 5 gallons water; foliar or soil drench. Same protocol as FPJ application.
The mistakes.
- Collecting from a depleted forest. Roadside oak that's seen herbicide drift has weak biology. Find healthy, undisturbed ground.
- Black or green mold on IMO-1. Contamination by aggressive molds. Throw the batch and try a different collection site. White mycelium only.
- Plastic containers for IMO-3. The pile needs aerobic breathing. Wood or burlap; not plastic.
- Letting IMO-3 cook too hot. Above 140°F kills the community. If pile gets too hot, turn it once to dissipate heat.
- Storing IMO-4 sealed in plastic. The community will go anaerobic and sour. Burlap, cloth, or wooden boxes.
- Treating IMO like a "shortcut." It's a 30-day succession from collection to application. You cannot rush the stages.
The compounding practice.
The first round of IMO takes a month. The second takes a week, because you can re-use a cup of IMO-2 as the inoculant for new IMO-3. The third round is reflexive. Once a property is running IMO on a quarterly cycle, the biology of the entire site begins to shift — not because you imported life from somewhere else, but because you took the life that was already adjacent and gave it room to expand.
That is the philosophical core of Korean Natural Farming, which Master Cho refused to call organic agriculture because organic still implies inputs you buy and apply. Natural farming asks a different question: what is already here, and how do we make more of it?
IMO is the answer at the microbial scale. The forest near you is doing the work. Bring some home; multiply it on rice and bran; introduce it to your soil. Within a season, the property begins to forget that it ever needed you.