IMO COLLECTION BOXES
IMO is the accepted acronym for Indigenous Micro-Organisms. It is a culture of soil biology collected and cultured from healthy local soil. IMO Technology was developed by Master Cho Han-Kyu of South Korea.
He developed it over decades of experimentation and implementation in diverse countries all over the world. It is the basis on which his Korean Natural Farming, KNF, was founded.
WHY USE IMO?
While it can take 200 years, on average, to create one centimeter of topsoil, IMO treatment can turn hard, rocky dirt into soft, plantable soil, to a depth of seven feet, in just three years.
Master Cho demonstrated this repeatedly in his work. It builds topsoil significantly faster than occurs naturally.
IMO is the most efficient way to create soil with high soil biology and activity. The reasons for this efficiency are:
1. Very high concentrations of soil biology
2. Installed as a complete, diverse, and intact ecosystem
3. A single application can be enough
When Master Cho describes why we use IMO, he explains that IMO can transform insoluble minerals into soluble minerals, and large particles of organic matter into smaller particles.
Both of these actions make nutrients, elements, and minerals easier to absorb, and the system (plant or animal) has less disease and greater immunity.
It brings in earthworms and other soil animals, building soil ecosystems and healthy environments. This builds soil tilth, structure, and mycorrhizal networks that enable plants to exchange nutrients and warn each other of dangers.
It even dissolves rocks into mineral components, in other words, turns rock into soil.
The soil microbes in IMO work synergistically with plants to free up nutrients that the plants need, on demand. This allows plants to uptake nutrients as they need them, in the proper amount.
This is the Natural State of plants, which is the state we are trying to achieve with Natural Farming. We want plants to be able to grow as the autonomous, life-affirming organisms that they are.
The first step in IMO Technology is to collect a culture of soil biology from local soils.
VITAL FORCES: The Three Chi
Before we cover the details of collecting IMO we need to understand a few basics about the principles of the Vital Forces, or The Three Chi.
Everything in Korean Natural Farming, KNF, is done by observing and applying the principles of the Vital Forces. This is in contrast to the modern agricultural paradigm of focusing on NPK (Nitrogen, Phosphorus, Potassium), etc.
The three Vital Forces are heat and sunlight, water and moisture, air and wind. Balancing these elements is important in order to keep plants and animals healthy, and is critical to IMO technology.
One of the most frequent patterns you will see in KNF is the ratio of one-third/two-thirds. For example, we will be filling the collection box two-thirds full, but leaving one-third as airspace.
You will see this ratio everywhere in KNF, especially when fermentation and cultures are involved.
Besides leaving one-third airspace so that the culture can breathe properly within the collection box, airflow into and out of the box is also vital. The box can’t be covered with anything that will disrupt that ability to breathe.
The box can’t be too big, or the ratios of gasses and solids, heat and cold, wet and dry, will alter what biology is collected, and we won’t get a good culture. The biology we collect is the foundation of our growing system, so this is a very important step to get correct. We need a complete, dynamically balanced, intact ecosystem from the soil.
Think about the air, the moisture, and the heat while going through these instructions. Most of the problems collecting IMO are caused directly by an imbalance of the Vital Forces. Learn to watch for these patterns when learning anything in KNF, not just the collection of IMO.
IMO COLLECTION MATERIALS
Collection Box (“lunch box”)
“Hard-cooked” rice
Proper collection site
Materials to protect the box from vermin and rain during collection, such as a cage and a tarp
Storage jar and dry, raw sugar to preserve culture immediately after collection
Collection Box (“lunch box”)
When we consider the collection box, which Master Cho refers to as the “lunch box,” we need to look at the size and the material.
Size
The ideal size of a lunch box (collection box) is rather small, about 30cm (12 inches) on a side and about 10 cm high (4 inches).
A lunch box this size will yield approximately a liter (quart) of IMO2, although you may get more than this or less, often more.
It takes only 5 grams (a teaspoon) to make a pile of IMO, which can weigh approximately 110 kg (240 pounds) finished. Again, your results may be different. A collection from this size lunch box will therefore inoculate approximately most of a hectare or about two or more acres.
If you are going to use KNF on a large operation and you need to collect more than this, make more collections rather than using larger collection boxes.
I strongly suggest avoiding any collection containers that are deeper than 10cm (4 inches). A deeper lunch box will require a deeper layer of rice to reach 2/3 full and will have a different balance of air and moisture. The layer of moist rice in a deep box will be thicker than ideal, altering the types of microbes collected.
Filling the container less than 2/3 full, easy to do with a deeper lunch box, will mean too much airspace, leading to the collection of sub-optimal and undesirable microbes.
Changing the dimensions of the lunch box will give poor results. A bigger box will typically be drier on the edges and wetter in the center. This will cause an uneven microbial collection and typically results in the collection of undesirable microbes.
When properly collected, IMO contains a naturally diverse community of microbes, spanning all kingdoms of life, with millions of species and billions of individual organisms. This dynamic stability of a complete ecosystem is what gives IMO its power.
This is the Power of Nature. This power is the main element that drew me to KNF and made it the focus of my life.
Every collection will include some anaerobes and potentially undesirable organisms like molds and pathogens, but the key lies in balance and stability.
An overgrowth of unwanted organisms actually reduces diversity and disrupts stability. It’s like a neighborhood where too many criminals move in without enough law enforcement to maintain order—chaos takes over.
Getting a good collection is the most important stage of the IMO Technology. Find or make a collection box as close in size as possible to 30cm by 30cm by 10cm high (one foot square by 4 inches high). Fill it with two-thirds “hard-cooked” rice, and leave one-third airspace.
Material
WOOD
Master Cho prefers to collect IMO using lunch boxes made from untreated Japanese cedar slats. These wooden boxes allow air exchange through small gaps, facilitating microbial entry while remaining durable, unbreakable, and easy to clean, and can give years of service.
UNGLAZED CERAMIC
Unglazed ceramic jars, traditionally used for fermenting kimchi, were the original IMO collection containers. Their porous structure allows gas exchange, creating a breathable environment for microbial growth. With proper care to prevent cracking, they can last for years and are easy to clean.
BAMBOO
Another container used since the early days of KNF is bamboo. Using larger bamboo varieties, a section of bamboo is split in half, the rice is added to the hollow interior, and the bamboo is put back together. The halves can be lashed together, which will prevent animals from being able to get to the rice culture. Bamboo works extremely well.
WOVEN BASKETS
Woven baskets are another effective option, though they do not last as long. They provide excellent breathability and often come with fitted lids. In regions like Hawaii and the Philippines, baskets made from pandanus (lauhala) are commonly used.
When selecting a basket, ensure the weave is tight enough to prevent rice from falling through. If necessary, a lining of unbleached muslin can help contain the rice.
AVOID GLASS, METAL, AND PLASTIC
Solid glass, metal, and plastic containers do not allow gas exchange, making the culture too anaerobic. For this reason alone, they should not be used.
These materials also present additional challenges:
Glass & Metal: Can cause heat loss and condensation, altering microbial composition.
Metal: May react with microbes, release toxic ions, disrupt pH, and interfere with microbial biofilms.
Plastic: Repels water, causes uneven moisture distribution, and creates anaerobic zones. It can create electrostatic buildup, which can repel certain microbes. It may also leach toxins and microplastics into the culture.
EXPERIMENTAL FINDINGS
I tested a stainless steel steaming basket with sufficient ventilation under stable temperature conditions. I used stainless steel because it is non-reactive. The results were acceptable, but the method would not be reliable when daily temperature fluctuations were more than a few degrees, or if other metals were used.
I also worry that electro-ionic effects may alter the collection, even though stainless steel is chemically non-reactive.
Plastic containers consistently failed due to poor air exchange and uneven moisture distribution, which interfered with the proper colonization of microbes. The margins where the culture touched the plastic were always slimy.
I suspect that the chemicals in the plastic, and perhaps the presence of microplastic particles, were involved, in addition to the lack of oxygen.
BEST PRACTICES
For a successful IMO collection, use breathable containers such as wooden boxes, unglazed ceramic, bamboo, or woven baskets. Avoid non-breathable materials like glass, metal, and plastic.
Use boxes that are approximately 30x30x10cm (12x12x4 inches) in size. Always fill with 2/3rds rice and leave 1/3 airspace. These practices ensure a stable and diverse microbial culture of a complete ecosystem.
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