Bokashi Composting: The Quick, Compact Compost Solution

Supercharge your soil using all your food scraps—meat and dairy included!—with this cool composting technique.

by Amy Grisak
PHOTO: Al Pasternak/Flickr

For the first time in years, we temporarily don’t have our little flock of backyard chickens to take care of our food scraps. When they left, I was at a loss for what to do with our vegetable waste, as I can’t say my compost pile is the epitome of an efficient system. I started it in the corner of the yard with the best of intentions, but once the rattlesnakes started making their appearance in midsummer, I wasn’t so keen on poking around in it!

Having perfectly good scraps and nothing to do with them is not a new phenomenon. According to the U.S. Environmental Protection Agency, the average household garbage consists of 14 percent once-edible waste. Of course, if nothing productive is done with scraps, they end up in overflowing landfills.

Fortunately, there is a way to process the kitchen excess at home and provide an exceptional boost to your garden. If you’re willing to step outside of the familiar compost pile that most of us know, fermenting food waste using “effective microorganisms” (marketed as EM-1) with bokashi cold composting is a convenient way to turn potential landfill fodder into something beautiful.

Bokashi (literal translation: “shading off” or “gradation”) isn’t new. Forty-five years ago, Dr. Teruo Higa, a horticultural professor at the University of Ryukyus in Okinawa, Japan, discovered a combination of microbes that fed the soil using key microbes. From there, he refined the discovery and learned of its far-reaching implications. For decades, this concoction of beneficial bacteria and yeast has been used in everything from cleaning up polluted ponds and water systems to mitigating animal waste odor. The microbial mixture is also the powerhouse behind bokashi composting.

The EM-1 liquid is often a mixture of wheat bran (although nearly any organic medium ranging from rice bran, bark chips or nut hulls will work) and molasses, which helps the good bacteria and yeast in the EM-1 serum thrive. The inoculated carrier is added on top of the food waste to break it down in weeks instead of months or years.

Aerobic Vs. Anaerobic

The first step is getting past the traditional image of how to compost. Traditional composting relies on naturally occurring fungi and microbes to break down vegetable matter. In order to do this efficiently, you need to create an ideal environment for them to turn the matter into compost without stalling out or overheating and turning it into a stinking pile of yuck.

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The basic recipe for a traditional pile is layering green materials (kitchen scraps, garden debris) and brown materials (leaves, dry grass clippings). It’s then a delicate balance of turning the pile to circulate air because the microbes require oxygen to break down the materials. It also must stay moist—not so wet that you can squeeze water from it but not dry enough to slow the process.

Heat is another critical component of traditional composting. On a positive note, temperatures between 130 and 145 degrees F are what kill pathogens and weed seeds. Unfortunately, as the temperature climbs so do the water requirements, as well as the release of gases, such as methane.

On the opposite end of the spectrum, bokashi composting requires an airless anaerobic situation in order to ferment properly. To visualize how it works, compare it to making sauerkraut without the brine. When anaerobic conditions are paired with the right microorganisms, the end result is a fermented product that stays nutrient rich.

“All of the nutrients stay in your bucket, so they go straight to the plants,” says bokashi enthusiast Morgan Coffinger, owner of Bokashi Evolution in Tempe, Ariz. One benefit of the bokashi method includes not using up the nitrogen in the materials to break down the organic matter, so nutrients are not wasted in the process.

Bokashi also handles weeds and pathogens without the heat. “The pathogens are killed by the acidity through fermentation; if you can eat it, bokashi is an option,” Coffinger says. Some people even add meat and dairy to their bokashi compost because it ferments and doesn’t pose the same problems as it would in a traditional compost pile.

Far-Reaching Effects

A practical consideration is that bokashi composting is easily accomplished indoors. If you’ve ever had a conventional compost bucket under the kitchen sink, you know it can become rank after a few days. Bokashi compost won’t do that. It might have a vinegar-like scent if the lid is off, but it won’t be putrid.

Michelle Bruckner of Tempe, Ariz., tried conventional composting off and on over the years. “It’s hard to compost in Arizona,” she says. “I was never able to get it to go.”

She started bokashi bucket-composting a year ago and loves it to the point that she will dig food waste out of her friends’ garbage to bring it home for her bucket. Not only is she reaping the benefits of food scraps from her family of four, she’s mitigating what goes into the landfill by “helping” friends.

The beauty is that bokashi is used all over the world. Coffinger says that if homeowners want to compost their food waste in New Zealand, they receive a subsidized bokashi inoculant and a bucket. This way, families are reducing the amount of waste going to the landfills and reaping the benefits of the end product.

Michael Dalton, aka Captain Compost through his Gardens from Garbage nonprofit organization in Great Falls, Mont., sees bokashi composting as a feasible way to keep a significant percentage of waste out of landfills, even if it’s one household at a time.

“Using the bokashi method, every ton of food waste produces 1 cubic yard of composted soil,” he says. This is gardening gold. It’s one thing to consider national statistics on average food waste amounts, but it’s another thing entirely to physically see what might go into the garbage.

For so many years, everything from food off of our dinner plates to vegetable parings went to our chickens. I never realized how much was truly there. When I started my bokashi buckets, it opened my eyes. Granted, it was toward the end of the season when we enjoy a bounty of produce from the garden, and grandparents also donated to the cause (because they’re used to sending old food up to the chickens), but on average, it takes me less than a week to fill a 5-gallon bucket. Throwing it in the trash would mean close to an extra bag in the dumpster. Multiply that by 52 weeks, and it’s enlightening.

Bucket Composting Basics

There are several ways to use bokashi in a bucket, and none of them really requires fancy equipment. “My buckets are just repurposed, food-grade, 5-gallon buckets,” Coffinger says. “People can make their own buckets that way.”

Option 1

The simplest method is using a single bucket, but the trick is dealing with the moisture generated during the fermentation process. “You don’t want a soupy mess,” Coffinger says.

When you’re using the single-bucket method, Coffinger recommends adding a cup of bokashi to the bottom of the bucket, then adding a good amount of crumpled up newspaper or cardboard before starting. This will absorb the liquid. You’re now ready to add layers of food waste. As you add each layer of food, including anything you wish to scrape off of your dinner plate, sprinkle a generous handful (or two if your hands are small) of bokashi. You want the entire food layer to be lightly dusted.

Once the bucket is full, press the food waste down and add more materials and bokashi before sealing the lid. Be sure the lid is snug, or the materials will begin to smell. I made that mistake in my first bokashi attempt, and my husband inadvertently tossed out the whole thing.

Set the bucket out of your way and out of the sunlight, as the UV rays can be detrimental to the microorganisms. I set mine outside the kitchen door in the garage. For the most part, it will not freeze (if the temperature dips to below zero, I’ll bring it inside), and it’s out of the way for the couple of weeks it needs.

Option 2

The next easiest option is to use a double-bucket system. Coffinger says to drill 25 half-inch holes along the bottom of the bucket to allow the “bokashi tea” to drain out. Place this bucket inside another whole bucket. Add a cup of bokashi to the bottom, and start adding your vegetable materials. You don’t need newspaper or cardboard because the liquid will drain.
Coffinger says to check the tea every other day by lifting the bucket and pouring out the precious liquid.

“It’s supercharged with awesome bacteria,” she says. “It works phenomenally well on frostbitten plants or any plants that ‘look sad.’ You can also pour it down your drain. It will break down any sludge you have in your pipes.”

To use the bokashi tea on your plants, dilute one tablespoon of the juice to a gallon of water. Water houseplants and outdoor plants with the diluted tea.

“It’s an excellent fertilizer—probably the best in the world,” Dalton says. He uses it on crops he grows in containers for various community projects.

Option 3

The third option for the bucket system is to use a bucket with a spigot on the bottom to pour off the tea. To drain the tea, simply open the spigot and tip the bucket slightly. Layer your food scraps and bokashi just like the other options.

Small-Scale Options

There are some people who simply don’t produce that much kitchen waste but still want to make a positive environmental impact.

“People even fill Tupperware containers with snap-on lids and keep them on their countertops,” Dalton says. He knows an elderly woman who composts in sandwich bags. She mixes the fermented food waste in containers on her porch, and her flowers are the envy of the neighborhood.

During the fermentation process, a white mold will probably develop over the food. That’s perfectly acceptable, and you don’t need to do anything. If there’s black mold, it is an indication of unwanted bacteria. Dalton recommends scraping it off and adding more bokashi.

Using Your Bokashi Compost

After a couple of weeks, once the fermentation process is complete, it’s time to work it into a carbon-rich environment to finish breaking down the waste. Don’t be alarmed when you open the bucket and the food still looks whole. Keep in mind, bokashi is a fermentation process. It basically pre-digests the food, allowing it to be quickly assimilated into the soil.

“Dig a trench in your garden bed, and dump it in,” Coffinger says. “Cover it with 4 to 8 inches of soil. Once you bury it, let it set for two weeks to allow the pH levels to balance out [before planting on it].”

Dump in the cardboard or newspaper as well if you’re using the single-bucket system. It takes four weeks for the bucket’s contents to completely break down in the soil.

Bruckner adds her bokashi mix to one of her four raised beds for the entire season. She keeps that particular bed covered with wood to keep her dogs out of it since they relish the fermented treasures. (This isn’t the case with all animals; some have more of a ferment-fetish than others.) Before planting, she turned up everything and was ready to go. This season she’ll add her bucket’s contents to another bed to supercharge that soil.

You can also add bokashi compost to your languishing compost pile to kick it into gear. For northern gardeners, Dalton recommends dumping it into a pile of leaves enclosed in either a compost bin or trash container. The microbes in the bokashi will break down the leaves, and you’ll have a fantastic amendment for the garden by spring.

Bokashi can also be added to a vermiculture setup, and I know of some insulated compost bins that keep worms going all winter long, partly due to the constant infusion of bokashi compost.

Even if you don’t have a garden, there should be no problem finding someone who would love to take your bokashi compost. If you personally don’t know any gardeners, chat with the local garden club or community garden. Gardeners cannot have enough organic matter for their gardens, so practically anyone would be delighted.

Composting with bokashi is a valuable tool for anyone who wants to reduce their waste footprint or who is looking for the next great soil amendment to grow exceptional plants. It’s simple, effective and can turn a lot of food waste into fuel for the garden.

This article originally ran in the January/February 2014 issue of Urban Farm.

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