Bokashi, the practice of fermenting kitchen waste to use in your garden and landscape, has long been practiced in Asia and is starting to gain ground in this country.

Contra Costa Master Gardener Bonnie Dwyer explained the art of bokashi at this week's Our Garden class.

Bokashi, Dwyer says, is the exact opposite of composting. Composting involves decomposition, breaking down food scraps and garden waste into a powerful soil additive that puts nutrients into the soil to feed the plants. Bokashi is about fermentation, and the end product can be a powerful soil amendment that makes it easier for plants to take up nutrients.

One is a fertilizer, one is soil conditioner, but working in tandem, composting and bokashi, can make for one impressive garden.

Here is what Dwyer had to say:

Origins

  • Bokashi was developed centuries ago by Japanese farmers who buried rice slurry and allowed naturally forming microorganisms to do their thing. Once the slurry had fermented, the farmers dug up the buckets and then added the solution to their soil.

  • Farmers believed the bokashi improved their soil, produced a higher quality and quantity of fruits and vegetables, and extended the shelf-life of the food -- all things researchers later confirmed.

  • Aerobic bacteria and fungi work together to cause the fermenting process that not only kills pathogens but encourages good bacteria.

  • Bokashi can soften hard soil and provide a medium that plant roots and beneficial organisms can easily move through.


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    Differences

  • Bokashi allows you to compost many things that you can't in a traditional composting system -- meat, fish, cheese and dairy products, desserts and even bones.

  • While items put in a composter break down and eventually become unrecognizable, what you put in the bokashi bucket comes out looking pretty much the same, just fermented. Dwyer compared it to making pickles. The cucumbers don't dissolve in the brine; they remain recognizable as cucumbers, but the pickling, or fermentation process, changes them.

  • While regular composting requires water and air to work, those two things are deadly to bokashi.

  • Bokashi produces results much faster than composting. It takes two to three weeks for the fermentation process to be completed.

  • Bokashi is not a fertilizer and will never replace your composter, Dwyer says. It should be used to augment your composting setup.

    How to do it

    You'll first need a bokashi bucket -- two would be better. These are available on the market, or you can make your own.

  • The key things needed are a mesh tray for the bottom of the bucket, a top to press down the material, a potato masher of some sort, a tightly fitting lid and a spigot to drain the liquid produced during fermentation.

    Fruits, meats and vegetables fermenting in a bokashi bucket.
    Fruits, meats and vegetables fermenting in a bokashi bucket. (Joan Morris/Contra Costa Times)

  • Once you have your equipment, you can start adding material to the first bucket. Start with a layer of bokashi inoculant, which you can make yourself or purchase.

  • Add in table and kitchen scraps. If you have very wet items, such as yogurt, add in a paper towel first and then add the food. Once you have about two inches of food items, use the masher and add in another quarter cup of inoculant.

  • Once you've finished adding scraps, place a cover directly over the food, weight it down and put the lid on. The goal is to keep out as much air and water as you can.

  • Fluid from the mixture should be drained every day, or at least every other day, through the spigot.

  • Keep adding material as you have it, and adding in the inoculant and resealing, until your bucket is full. Then add inoculant and set the bucket somewhere out of the light and heat, such as a closet, and leave it for two to three weeks. Continue to drain it regularly.

  • Once it's fermented, open the lid and behold. You should find a white mold growing on the material. If it's black or any color other than white, then something has gone wrong and, as Dwyer says, you've lost your bucket. Don't try to use this in your garden.

  • While one bucket is in the final fermentation, you can start filling the other one.

    What to do next?

  • Once you have your finished product, you can use it in your garden by burying it. Dig a trench at least 12 inches deep, and cover the material with 8 to 10 inches of soil to keep animals from digging it up.

  • Trenches should be at least 12 inches from existing plants, so it's best to use bokashi in empty beds.

  • Wait two weeks before planting in the bed.

  • Dwyer says she uses the bokashi in her existing compost piles, by digging down and then covering the bokashi with the remaining compost.

  • Bokashi must be buried to work.

  • You also can use the liquid drained from your bokashi bucket, but you need to dilute it.

  • For lawns, use one part bokashi to 100 parts water; for gardens, the ratio is one part to 300 parts; for succulents, one to 500; and as a foliar feed, one to 1,000. That's about ¾ of a teaspoon of bokashi liquid to a gallon of water.

  • Bokashi fluid must be used within 24 hours, and applied in the evening to avoid sun exposure.

  • Bokashi fluid can be applied once a week.

  • Because you produce more than you'll need in the garden, Dwyer suggests using it to keep your pipes and plumbing clean. Flush it down the toilet or down the sink, adding lots of water to wash it through.

    Making inoculant

  • You easily can make your own by taking 2 pounds of wheat or rice bran; 2 cups of water with 1 teaspoon of unsulfured molasses and a teaspoon of EM1 (Effective Microorganisms).

  • Mix the solution into the bran, mixing well to coat the bran and break up any lumps.

  • Pour into a plastic bag, squeeze out as much air as you can from the bag, seal it and store in a cool, dark place for about two weeks.

  • On a calm day, spread a tarp in a shady area and spread out the mixture. Every hour or so, rake the mixture until you are certain it has dried throughout.

  • Pack it in a resealable bag, squeezing out the air, and use as needed.

    Sustainability Fair

    Our Garden will again host the Contra Costa Sustainability Fair, 10 a.m. to 3 p.m. Sept. 6. More than 30 organizations will be on hand offering information and advice on a variety of topics including raising chickens, saving water and growing a drought resistant garden. Admission is free, and there will be winter seedlings and drought tolerant ornamentals for sale.

    Our Garden

    Our Garden offers free gardening classes 10 a.m. to 11 a.m. every Wednesday, through October. The garden is located at Wiget Lane and Shadelands Drive in Walnut Creek. Master Gardeners are available to answer your questions and diagnose disease and pests, and there is a wide variety of plants for sale.

    Next time in the Garden: Annual tomato tasting.