The Basics of Bokashi Composting

Composting is not only for gardeners though they usually have lots of organic materials. 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 in. This method 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, its benefits, and what you need to start.

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 sell replenishment products, including effective microorganisms and bokashi bran. Here are steps for DIY bokashi composting:

1. Chop food waste into 1- to 2-inch pieces. If you add larger pieces, they will take longer to ferment.
2. 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 add fluffy scraps, press them down to remove the air or put a plate or another flat, heavy object on top of the material to weigh it down to limit oxygen exposure.
3. Once the bin is full, keep it closed, and let it sit in a warm place for at least two weeks. During that time, drain the bokashi tea every few days. When the bokashi pre-compost is ready and fermented, you don't need to use it immediately. It can sit in the bokashi bucket for longer. During that time, the microbes will go dormant until you use it.

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 high in nitrogen, brown materials high in carbon, and air and water. 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. Because bokashi compost bins are usually small and used indoors, there is no room for 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 amount of moisture. If the content is too dry, add enough water to moisten it without becoming soggy. Keep adding moist items regularly. If the content is too wet, drain the bin regularly to remove excess liquid.
• Foul, putrid odor, and/or blue/green mold: This problem signals that fermentation is not properly happening. Odor or mold could be caused by the seal not working 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: The fermentation process slowed down from a lack of bokashi bran or because the temperature in the bucket was too hot or cold. To ensure fermentation, maintain the recommended temperature range for bokashi composting between 60°F and 80°F.

Ways to Use Bokashi Compost

The end product of bokashi composting is different from traditional composting which is ready to be used in the garden as is.

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, 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 possible 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, and about a week longer in cold weather. If you want to use bokashi compost for your lawn, safely mix it with other compost before spreading it.