How to Make IMO: Collecting and Cultivating Indigenous Microorganisms

Indigenous Microorganisms (IMO) is the Korean Natural Farming method for capturing and cultivating the local microbial community — fungi, bacteria, yeasts and actinomycetes — from a nearby biodiverse environment and transferring them into your garden. The premise is that organisms already adapted to your local climate, soil type and plant species are better suited to your growing environment than organisms cultured in a laboratory in another region.

IMO is a four-stage process. Each stage takes the microbial community from the wild collection (IMO-1) through progressively larger volumes to a scale practical for field or garden application (IMO-4). It requires patience and a nearby ecosystem to collect from — a forest, woodland edge, or biodiverse hedgerow works. Urban rooftop growers with no access to healthy soil or established woodland have limited options for genuine IMO collection.

What you are collecting

The target organisms are those that colonize and decompose organic matter in healthy, biodiverse soil: white mycelial fungi (Trichoderma, Aspergillus and related species), Lactobacillus and other beneficial bacteria, yeasts, and actinomycetes. All of these are naturally present in the upper layers of undisturbed forest soil, under decaying leaf litter and on decomposing logs.

White fuzzy mycelial growth — the same general appearance as beneficial fungi on a grain jar — is the primary indicator of a successful IMO-1 collection. Colorful molds (green, black, orange) indicate contaminant organisms and the collection should be discarded.

IMO-1: Collecting native organisms

Materials:

• Cooked rice (plain, no salt, oil or seasonings): about 1-2 cups
• A small wooden box or cardboard box that breathes (not plastic, not airtight)
• Cheesecloth or breathable fabric
• A rope or stake to hang or anchor the box in location

Process:

1. Cook rice and let it cool completely. Pack it loosely into the wooden or cardboard box to a depth of 2-3 inches. The rice must be cool — warm rice will inhibit the organisms you are trying to collect.
2. Cover the top of the rice with a single layer of cheesecloth. Do not seal the sides or bottom.
3. Take the box to your collection location: a forest floor, under deciduous trees with active leaf litter, or near a productive compost pile. Ideally, a location with visible fungal mycelium or healthy microbial activity in the soil.
4. Set or hang the box so it rests in contact with the organic layer of the soil, or just above it. The goal is proximity to the soil biology without the rice being buried.
5. Cover the box loosely with leaves or bark to protect from direct sun and heavy rain, but not so tightly that air movement is restricted.
6. Leave for 3-5 days. Check on day 3. You are looking for white fuzzy mycelial growth on the surface of the rice. This indicates successful colonization by the target organisms.
7. Successful collection: white fuzzy growth, earthy-mushroom smell. Collect the box and move to IMO-2 immediately.
8. Failed collection: no growth after 5 days, or only colored mold growth. Move to a different collection location and repeat.

Timing: IMO collection works best in warm, humid conditions. Spring and fall are often ideal. Dry summer or cold winter conditions slow or prevent successful collection.

IMO-2: Preserving the collection

IMO-2 converts the short-lived IMO-1 culture into a stable, long-term concentrate by preserving the organisms in sugar.

Materials:

• IMO-1 rice culture (the colonized rice from the collection box)
• Brown sugar: equal weight to the rice culture

Process:

1. Weigh the colonized rice.
2. Mix thoroughly with an equal weight of brown sugar. The sugar osmotically draws moisture from the rice while preserving the microbial community in a dormant, stable state.
3. Pack into a container, press down to remove air pockets and seal.
4. Store in a cool, dark location. IMO-2 keeps for 6-12 months. It should smell earthy and slightly sweet, not rotten or ammonia-forward.

IMO-2 is the storable form of your culture. Make it in sufficient quantity to have material available for multiple IMO-3 batches.

IMO-3: Creating a soil inoculant

IMO-3 reactivates the IMO-2 culture by introducing it to a nutrient-rich organic substrate. The organisms wake up, multiply and colonize the substrate. IMO-3 is then used as a soil amendment — essentially a homemade biological inoculant applied directly to growing beds.

Materials:

• IMO-2 (your stored culture): 1 cup
• Brown rice flour or wheat bran: 100 parts (by weight, relative to IMO-2)
• Water to achieve 60-65% moisture content (the material should hold its shape when squeezed and release only a drop or two of water, not stream)
• A large container or pile with some breathability

Process:

1. Combine IMO-2 with the grain flour and mix thoroughly.
2. Add water gradually while mixing until the 60-65% moisture target is reached.
3. Shape into a pile or pack into a container with some breathability (not sealed). Cover with burlap or breathable cloth.
4. Leave at room temperature for 5-7 days. The pile will warm slightly as microbial activity increases — target internal temperature is 100-120°F. If it exceeds 130°F, the heat is killing the organisms: turn the pile to cool it.
5. White mycelial growth should appear throughout the substrate within a few days. A strong earthy, slightly sweet smell indicates active microbial growth.
6. When the substrate is fully colonized (white mycelial growth throughout, earthy smell, temperature has peaked and begun declining), IMO-3 is ready to use or store.

Storage: dried IMO-3 (spread to dry at room temperature, not heated) keeps for several months.

Application rate for IMO-3: 1-2 cups per 100 square feet of bed, worked into the top 2-4 inches of soil. Apply 2-3 weeks before planting or at the beginning of the growth cycle.

IMO-4: Scaling for garden application

IMO-4 is the practical, field-scale application stage. It introduces IMO-3 into a large volume of organic material — compost, wood chips, straw, or a combination — to produce a bulk biological amendment for large gardens or raised beds.

Materials:

• IMO-3: 1 part
• Compost, straw, or wood chips: 100 parts
• Water, local soil amendments (optional)

Process:

1. Mix IMO-3 thoroughly into the dry organic material.
2. Bring moisture to 60-65% (same test as IMO-3 — squeeze and check).
3. Pile and cover as before. Allow to ferment and colonize for 5-7 days.
4. Apply directly to garden beds. IMO-4 is both a biological inoculant and an organic matter amendment — it adds living organisms and organic material simultaneously.

Most home and small-scale growers work primarily with IMO-3 and skip IMO-4, which is more relevant for larger agricultural applications. IMO-3 applied directly to beds at the rates above is fully effective for garden-scale growing.

The practical minimum for home growers

If you are growing in containers or a small indoor space, IMO-1 through IMO-3 is the relevant range. The collection (IMO-1) is the bottleneck — it requires a good collection site. If you do not have access to biodiverse local ecosystem for collection, IMO is not the right tool for your situation. Commercial biological inoculants (mycorrhizal fungi products, PGPR inoculants) serve a similar function without requiring wild collection.

For the flowering stage specifically, the biological inputs delivered by a well-made FFJ — LAB cultures, organic acids that feed rhizosphere biology, the amino acids and compounds that support an active microbial community — address rhizosphere biology directly without the multi-stage IMO process. [Join the waitlist for our FFJ formulas] to be notified at launch.