The Basics of Bokashi Composting

Composting is not only for gardeners though they are usually the ones with lots of organic materials on their hands. But even if you live in an apartment, you can compost to cut down on waste that goes to the landfill and instead produce a material that returns nutrients to plants, including your houseplants. However, not everyone has outdoor space for a compost bin. That’s where bokashi composting comes into play, a composting method that is fundamentally different from other forms of composting. It is an anaerobic process that ferments food waste in an indoor kitchen composter and turns it into compost tea and pre-compost.

Read on to learn about the bokashi process and what you need to get started.

What Is Bokashi Composting?

Bokashi is a Japanese word meaning "fermented organic matter." Developed in the early 1980s by Dr. Teuro Higa, a professor at the University of the 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 serve as the food for the microorganisms, which are the same natural microorganisms found in soil.

How to Get Started With Bokashi Composting

Build your own system or buy a complete bokashi composting kit. Companies that sell the kits usually also sell replenishment products, including effective microorganisms and bokashi bran.

Chop food waste into 1- to 2-inch pieces. If you add larger pieces, they will take longer to ferment.

About once a day or every two days, add a small sprinkle of bokashi bran, about 1 tablespoon per inch of food waste. Open the bin only to add scraps, not to check on the state of the fermentation. If you are adding lots of fluffy scraps, press them down to remove the air. You also place a plate or another flat, heavy object on top of the material to weigh it down and limit the oxygen exposure.

Once the bin is full, keep it closed and let it sit in a warm place for two weeks. During that time, drain the bokashi tea every few days.

Bokashi Composting vs. Traditional Composting

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 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. In essence, the bokashi process is a fermentation process rather than a traditional composting method.

A big difference between bokashi and traditional composting is that you are less restricted in what you can compost. Any food waste, including dairy and meat, is fair game. However, bokashi compost bins have more space limitations than traditional compost bins. As bokashi compost bins are usually for indoors and small, there is no room for any garden waste, such as grass clippings.

The Pros & Cons of Bokashi Composting

Troubleshooting Bokashi Composting Issues

Insufficient or too much moisture: The fermentation process inside the composter requires a certain level of moisture. If the content is too dry, add a moderate amount of water, just enough to moisten it without getting it soggy. Also make sure to keep adding moist items on a regular basis. If the content is too wet, drain the bin regularly to remove excess liquid.

Foul, putrid odor and/or blue/green mold: This shows that fermentation is not happening as it should. This could be caused by the seal not working properly so air got into the bin or by adding too much of one type of food waste. Check the seal, open the bin as infrequently as possible, and try to add a balanced mix of food scraps.

No fermentation taking place: The cause for this is either a lack of bokashi bran or a temperature that is too hot or too cold, either of which can slow down the fermentation process. The recommended temperature range for bokashi composting is between 60 and 80 degrees F.

Ways to Use Bokashi Compost

The end product of bokashi composting is different from traditional composting which can be used as is in the garden and on plants.

With a pH between 4.0 and 5.0 (or even lower depending on what went into the bin), both bokashi tea and pre-compost are quite acidic. Bokashi tea cannot be used as a fertilizer on houseplants or garden plants directly, it needs to be diluted first at a rate of about 1:100. Add 1 tablespoon of bokashi tea to 6 ¼ cups of water. For acid-loving plants such as azaleas, you can use slightly less diluted water of about 1:80.

Add the bokashi pre-compost to a traditional compost pile, large planters, or garden soil. Because of its high acidity, distribute the pre-compost as evenly as you can to avoid it being concentrated in one spot. It takes about two weeks for the bokashi pre-compost to be absorbed by the soil web, about a week longer in cold weather. If you want to use bokashi compost for your lawn, it is safer to mix it with other compost before spreading it.