The Basics of Bokashi Composting

Nearly every or would-be gardener knows that that composting is a good practice for the garden and for the environment, but not everyone knows there are many ways that composting can be practiced. At a basic level, all composting is a process by which organic materials are deliberately decomposed in a controlled fashion to produce a material that can be used to return nutrients to the soil. The recipe for traditional composting is a mixture of "green" materials that are high in nitrogen, "brown" materials that are high in carbon, along with air and water.

But within the broad definition, there are many ways to practice composting.

• Simple on-site composting in which pretty much all organic scraps and refuse (except for meat products) are heaped together and allowed to decompose.
• Vermicomposting uses red worms to hasten the breakdown of organic materials.
• Windrow composting is high volume composting using long rows of organic materials that are aerated regularly.
• Static-pile composting involves piling up organic matter to be broken down by bacteria.
• In-vessel composting takes up the least amount of space because organic materials are collected in a drum or vessel to be manually or mechanically turned and mixed.
• Bokashi composting is quite different than other methods. While it takes some special equipment and materials, Bokashi composting requires only about 10 days to convert organic materials into useable material, and the nutrient value of the material is among the highest of any method of composting.

How Bokashi Composting Works

Bokashi is a Japanese word meaning "fermented organic matter." Developed in the early 1980s by Dr. Teuro Higa, a professor at the University of Ryukyus, Okinawa, Japan, the method involves layering kitchen scraps (vegetables and fruits, as well as meat and dairy scraps) with a Bokashi inoculant in a special bucket. Usually, the inoculant consists of either wheat germ, wheat bran, or sawdust combined with molasses and effective microorganisms (EM). The bran/molasses serves as the food for the microorganisms, which are the same natural microorganisms found in soil. You can make your own system or buy complete Bokashi composting kits online, from garden stores, or natural living retailers, which also sell the replenishment products, including the effective microorganisms and bran/molasses.

The Bokashi bucket has an air-tight lid and a spigot at the bottom to drain off the liquid that is produced. The liquid must be drained off to prevent the bucket from developing a somewhat foul odor, but the liquid serves as a very nutritious "bokashi tea" that can be used to fertilize houseplants.

When layered and left to sit out of direct sunlight, the mixture quickly begins to ferment, and within 10 days the fermented mixture can be dug directly into the garden or added to a traditional compost bin or pile to finish its decomposition. In essence, the bokashi process is a fermentation process rather than a traditional composting method.

Unlike traditional composting, which is an aerobic process that requires oxygen, Bokashi is an anaerobic process that requires that you isolate the materials from oxygen as much as possible. The bucket should be opened only to add scraps, not to check on the materials. Some people recommend pressing the food waste into the composter to squeeze out the air, then leaving a plate (or another flat object) resting on top of the material to shield it from exposure to oxygen.

Bottom Line

Bokashi composting is categorically different than other forms of composting since it is an anaerobic process that ferments organic material rather than fully decomposing it. Although it requires special equipment and materials, bokashi composting produces byproducts in a very short time that are highly nutritious for plants and can serve as "fuel" for other forms of composting.