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Bokashi can boost beneficial microbes in the garden

“A century ago, many products that we think of as ‘waste’ were cherished as sources of garden fertility.”

— Anna Hess, “The Weekend Homesteader,” 2012

Kitchen scraps are an excellent example of what author Anna Hess describes as free household biomass that can be turned into compost for healthy garden soil. Vegetable and fruit peelings, tea bags, coffee grounds and stale bread can be used to introduce organic matter and beneficial microorganisms to our soil and plants.

The tricky part is using food leftovers in ways that won’t stink or attract rats and other varmints to the compost bin or growing area. That’s where bokashi composting can play an important role in helping gardeners reduce food waste, and the use of store-bought fertilizers.

The Japanese word “bokashi” was originally used to describe a shading or fading process for artwork. In the early 1980s, a horticulture professor named Teruo Higa introduced a process for fermenting food waste that became known as bokashi composting.

Bokashi is a mixture of beneficial bacteria and yeast grown in a grain-based substrate such as wheat mill run, the byproduct of wheat processing. By introducing microbial enzymes to food scraps under anaerobic conditions, bokashi pickles the biomass (think kimchee or sauerkraut) and speeds up the process of breaking down nutrients.

Bokashi can be used to break down material that is not usually compostable, such as bones and dairy products. The bokashi mixture also eliminates the odor of decomposing food scraps (it can even be used in kitty litter or in animal bedding).

Evan Short, who owns Southern Oregon Bokashi in Talent explained the process for fermenting kitchen scraps with bokashi:

Spread 1 to 2 tablespoons of dry bokashi in the bottom of a five-gallon bucket, add an inch-thick layer of kitchen scraps, and cover with another layer of dry bokashi. Continue this layering process, making sure to firmly compact the layers to remove oxygen as you go. Once the bucket is full, allow 2 weeks for the fermentation process to complete.

The bucket of fermented kitchen scraps can be layered with straw and other biomass into a compost pile or trench.

If you use a container with a false bottom and spigot, liquid from decomposing food scraps can be captured, diluted with water, and applied to garden soil as a nutrient-rich tea. (Evan said undiluted liquid can be poured down the sink to unclog drains.)

Bokashi tea can be mixed into the soil around plants or used as a foliar application. Dry bokashi can also be added directly to compost or broadcast over planting soil as an inoculant. Some growers use composted bokashi as a top dressing for garden beds, and then add a layer of mulch.

Lactic acid bacteria in bokashi reduce populations of root-feeding nematodes in the soil, as well as particular species of Fusarium fungi that produce plant diseases like Fusarium wilt and blight. Another kind of beneficial bacteria in bokashi, called Bacillus subtilis, has shown effectiveness as a foliar application to ward off fungal diseases such as gray mold and powdery mildew.

The B vitamins in bokashi help mitigate the effects of transplant shock when planting out new starts grown indoors or moving plantings with established root systems.

Evan said he compares a plant leaf to a petri dish, in which all kinds of microbes — friend and foe to gardeners — compete for food and space. Bokashi provides a booster shot of microorganisms that are good at outcompeting the bacteria and fungi in the petri dish that cause plant diseases. Thus, the population of beneficial microbes increases to help plants photosynthesize efficiently and protect the plant’s vascular system from parasitic invaders.

Evan started Southern Oregon Bokashi in the Applegate Valley in 2010 to support organic agricultural practices. His microbial soil amendments are available at his Talent store, on his website, and at several retail locations in Grants Pass, Medford, Phoenix and Ashland. For more about bokashi, see www.sobakashi.com.

Southern Oregon Bokashi will be at the upcoming presentation of the film “Fantastic Fungi,” based on the book of essays edited by mycologist Paul Stamets. I’m eager to see if the cinematography in the motion picture captures the mysteriousness and magnificence of mushrooms equal to the book’s vivid photographs.

“Fantastic Fungi” will show at 7:45 p.m. Thursday, March 26, at the Varsity Theatre, 166 E. Main St., Ashland. Proceeds will benefit Our Family Farms, a nonprofit that supports regenerative agricultural practices.

For information or to purchase tickets, see www.ourfamilyfarms.org.

Rhonda Nowak is a Rogue Valley gardener, teacher and writer. Email her at Rnowak39@gmail.com. For more about gardening, visit her blog at http://blogs.esouthernoregon.com/theliterarygardener/ and check out her podcasts and videos at https://mailtribune.com/podcasts/the-literary-gardener, and her website at www.literarygardener.com.