Shig Matsukawa spends most days volunteering at some of Manhattan’s 139 community gardens. Like any skilled gardener, he wears gloves and in hand has his cultivator, a small fork-like tool used to break up soil and uproot weeds. In New York, however, Matsukawa is a master of bokashi, an ancient composting technique he studied in Japan.
Unlike standard composting, Bokashi works on food scraps and ferments them in an air tight environment. According to Matsukawa, fermentation is the safest way to compost, as fermentation eliminates any toxins from food waste, especially meats and dairy, that could harm the soil it gets planted in. The bokashi is then mixed into garden soil where organisms like worms, pillbugs and bacteria break it down to nutrients palatable by plants. Matsukawa’s success with bokashi, however, depends on a constant stream of food scraps from nearby residents who donate them as part of a city-wide food scrap collection program.
On a recent Saturday in April, Matsukawa explained the chemistry behind bokashi to a group of seven people with varying levels of interest. Joy Doherty, an attendee who made her own kombucha at home, watched in rapt attention. Her friend Cecilia Covais was less interested, wishing she were across the street where the sun was. “The things you do for your friends,” she said, shaking her head as Doherty took notes.
Matsukawa pointed the class toward a food scrap shredder, a wooden contraption with a ship wheel attached. The garden had received a grant to purchase the $800 shredder from a German manufacturer designed to break down plastics to be used in 3-D printers. But it worked as well for orange peels and avocado pits. The wheel had not been included, though, and a local welder added it.
Matsukawa warned the class that avocado pits could be tricky to shred — he took a small log and held the pits against the teeth of the shredder so they could latch on. Bits and pieces began to fall through as Doherty stared in amazement.
As it turns out, the decision to shred food scraps makes a huge difference in the smell of the fermentation. Matsukawa opened a 20-gallon airtight tub of month-old, unshredded, fermented garbage, brought his nose down to it, and took a long whiff.
“Can you smell that vinegar?” he asked.
“It’s lemony!” Doherty said.
Next, Matsukawa opened a tub of shredded fermented scraps and another attendee sniffed.
“It smells so good!” she said.
Matsukawa said the smell of bokashi is a good indicator of its quality — the better the bokashi, the better the smell.
“Especially if you do it in your apartment,” he said.
Matsukawa is approaching 50, kindly and bespectacled with unruly, salt and pepper hair. As a visiting student at the University of the Ryukyus in Okinawa, Matsukawa traveled to Japan in 1993. With the encouragement of his parents, he spent two years studying bokashi and horticulture under Professor Teruo Higa. Higa was founder of the EM Research Organization (EMRO), which conducts research on microorganisms in soil and water environments. On behalf of EMRO, Matsukawa traveled the world, teaching bokashi in places like Guam and Tonga. In 2009, he began introducing the fermentation process to New York City.
After the food ferments, usually in two to four weeks, it is placed into a worm bin, a large wooden crate lined with chicken wire. The bin is full of natural soil that contains bugs, worms, and bacteria to break down the bokashi and release its nutrients. Matsukawa opened the bin and digged through soil with his cultivator, unafraid of slicing a worm in half. Doherty peeked in and the exposed slimy, pink bodies dove back into the soil to escape the disturbance.
“When you see so much life, it’s doing the right thing,” Matsukawa said.
Like human activity, the activity under the soil produces heat. Matsukawa held his hand over the hole he had just dug, like it was a campfire warming his cold hands. One by one, attendees held their hands over the hole to feel the heat escaping from the soil, easily ten degrees warmer than the temperature outside, although it should have been frozen solid.
Matsukawa told the class that bokashi is the most effective method of composting. The fermentation process, he explained, changes the chemical makeup of the scraps and makes them easier for microorganisms to break down and for plants to consume. It also enriches the soil and encourages life underground. He claimed that had farmers in the prairies used bokashi, the devastating Dust Bowl of the 1930’s would never have happened.
“They were feeding the plants directly with chemicals without paying attention to the soil underneath,” he said. “It all dried up.”
The class moved on to the El Sol Brillante garden down the street to make their own bokashi. The scraps are fermented using a recipe of commercial wheat bran and an amber-colored liquid called EM-1, which contains lactic acid bacteria, yeast, phototrophic bacteria, and water. Matsukawa drinks a gulp of it every day and claims it saved him from an E. coli infection he contracted once in Egypt.
For bokashi, however, he instructed the class to mix the EM-1 with blackstrap molasses to activate the bacteria and then pour it into bins of wheat bran, which the bacteria feed off of. After two weeks, Matsukawa would sprinkle the mixture over food scraps and leave them for several more weeks to ferment before transfer to the worm bins.
Doherty asked why everyone wasn’t doing this and Matsukawa said that the practice is not well-known outside of Japan. After his studies in Japan, Matsukawa was eager to share his discoveries with other agriculturists and horticulturists. He cited a gentleman who tried to create a bokashi program for food growers in the United States — the millionaires who could fund the project, however, were more interested in patenting the technique. Bokashi could not be patented and the program never launched.
“I thought this could change the world,” Matsukawa said, “but then I realized that the way our world works is not compatible with bokashi.”