If worms make you squeamish and you don’t have room for a traditional composter outdoors, why not give bokashi composting a try? Unlike other composting methods, bokashi, which means “fermented organic matter” or “gradation” in Japanese, is a closed, anaerobic system.
Because air does not mix with compostable wastes, bokashi is highly efficient and is capable of breaking down organic matter much faster than other composting systems. Bokashi composting bins take up very little space and the whole process takes place indoors.
Bokashi composting employs a combination of up to 80 different microbes called Effective Microorganisms (EM). First developed by Dr. Teruo Higa in Japan in the 1970s and marketed a decade later, EM is a specialized balanced formula of bacteria and yeast which is mixed with a carbon base such as wheat bran and a sugar (usually molasses). EM lies dormant until combined with organic wastes in a sealed system, whereby the microorganisms activate. The fermented matter created is a source of significant nutrition to plants.
Bokashi systems can compost a wide range of food wastes, including fruits, vegetables, grains, coffee grounds, tea bags, egg shells, and small amounts of cooked and raw meat, fish, cheese, eggs, and bread. Paper coffee filters and facial tissues may also go in the bin, as can plant clippings that have been chopped into small pieces. It is essential that you don’t overload your bokashi system though — it is always better to add only a small amount of waste, once a week.
The contents of your bokashi composter can take between 14 and 30 days to ferment, so it may be useful to set up a second bin and run the two systems in conjunction with one another. While you wait for your bins to complete their cycles, you can store excess food wastes in a container in the freezer, to be placed in the composter at a later date. Freezing the scraps helps keep the fruit flies away.
Plans for DIY bokashi bins are easily found online, or you can buy ready-made buckets at any store that sells “green” or environmentally-friendly products. No matter which type of bin you select, it is imperative to choose one that is tightly sealed, as one of the keys to success with bokashi is the lack of air in the system. A constant supply of EM is required to keep the system going. While it is possible to “breed” the inoculant and make your own grain blend, it is easiest to buy the microorganisms already pre-mixed with bran and sugar from a supplier. Bokashi bran containing EM can be purchased at any place that sells the buckets, and it is widely available online.
Set up your bokashi system by sprinkling a small amount of bokashi bran into the bottom of the bin and topping with food scraps. Use about 4 ounces of bran to every 2 inches of waste, unless you’re adding dairy or meat, which will require the addition of more bran. Push as much air out of the pile as possible by pressing the food waste down with an old spoon or spatula. Close the lid and let the EM get to work. Add layers of food waste and bran until the bucket is completely full — but remember not to open the lid too often, as the system only works if completely enclosed.
Bokashi composting will produce leachate, which should be drained off every two weeks. The chunky wastes should remain inside the bucket. The leachate can be diluted with water at a ratio of 1 tsp of “juice” to 100 ounces of water and used as fertilizer for your garden or houseplants plants. Do not store unused portions of bokashi liquid.
Successful bokashi compost should smell slightly sour when you open the bucket. If the wastes start to grow mold, destroy them. Clean the bins with hot soapy water and restart your system. One of the differences between bokashi and other composting methods is that the food scraps will not completely decompose in the bin. It is necessary to bury the fermented matter outside in the soil or in a traditional compost bin to further break down the wastes. Once buried, the beneficial microbes in the waste immediately begin to feed the soil. Bokashi compost is extremely rich and can actually burn the roots of plants, so be careful how (and where) you dig it in. Use it sparingly.