July 24, 2024

How do I compost at home? New technology makes going green easier

How do I compost at home? New technology makes going green easier

(Video: Illustrations by Tara Jacoby for The Washington Post)


Few know this, but I have 3,000 employees working for me at home. They don’t punch a clock, but they toil day and night. We never speak, but we meet for a few moments every few days. I supply them with as much food as they can eat, and in return, they furnish an endless supply of black gold.

Composting is something most people assume they can’t or won’t do. And I get it. I was once a non-composter too. I’ve heard about the potential problems: The smells, the flies, the rats, it’s a hassle, no space, an unspoken fear of the unknown. I, too, have battled the fruit fly.

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But it turns out, these problems are all avoidable. A new crop of ways to compost has emerged over the past few years. American composters are a growing breed. Their numbers have ticked up over the years thanks to more municipal collection programs — mandatory in states like Vermont — as well as growing interest among those aware of the impact, and value, of their kitchen scraps.

It’s also much easier. New technology and services are available to meet that demand, whether you want a sleek appliance or a ready-made worm farm. If you aren’t composting yet, get ready. As the country aims for net-zero emissions, composting may start to become as common as recycling. Plus, you’ll get the best tomatoes of your life.

The food waste problem

Americans have never wasted so much food: 400 pounds per household. That’s about 35 percent of the total U.S. food supply ending up in the trash, according to ReFED, a California-based nonprofit organization dedicated to ending food waste.

Today, Americans compost about 6 percent of kitchen scraps. The rest ends up mainly in landfills where it rots, generating methane, a greenhouse gas 80 times more potent in the short term than carbon dioxide. Virtually none of our food waste ends up as compost fertilizing our yards or fields, depriving the soil of many of the nutrients that must be added with natural-gas-derived nitrogen fertilizer.

Homes generate most of the emissions from wasted food in the United States. It’s not just vegetables, leftovers and overripe avocados being squandered. It’s also the energy that went into plowing fields, fertilizing crops, running tractors and then trucking food to get it onto your plate. Most food-related emissions, it turns out, are generated long before your scraps hit the landfill.

Yet, unlike other forms of waste, there is little social stigma or cost attached to it. “If you were to walk down the street and throw half a bag of potato chips on the sidewalk, people would look at you as if it were an awful offense,” says Dana Gunders, executive director of ReFED. “But if you throw it in the garbage can, they don’t think much of it.”

Composting, unlike recycling, has yet to gain mainstream acceptance. This is changing slowly. At last count, nine states have restricted sending food waste to landfills. Vermont is the first state to ban the disposal of food scraps in the trash or landfills for households.

Some cities are trying to scale up composting: Austin gives residents vouchers to buy compost bins. Los Angeles County discounts them for residents. But commercial composting hasn’t been scaled up to match our municipal waste stream. Doing so will require more than $1 billion, according to ReFED estimates. Of the 5,000 composting facilities nationwide, only 500 accept food scraps, ReFED estimates.

So for now, composting friends, most of you are on your own. Luckily, you need not share my admiration for red wigglers to compost.

What’s the best composting setup for you?

For this I turned to Amy Landers, who runs Gardens That Matter, an online gardening club offering classes and a community to help people garden. Her composting credentials date back to an eighth-grade science project, and she now composts on her farm outside Asheville, N.C. Her largest composting venture? The dead horse of a neighbor, whose owner couldn’t bear to send her beloved pet to the landfill. Everything but the bones was gone in about a year.

Most people, says Landers, overthink composting. “If it was ever alive, it can be composted,” she says. A large, hot, well-run compost pile — no trivial feat — can digest almost any organic matter, eventually. But even something more modest in your backyard can handle quite a bit.

In fact, most of the organic materials coming into your home from groceries to junk mail to paper bags are just soil in waiting. Think of compost as a luxury high-rise for microorganisms. Bacteria, fungi, nematodes, worms, sow bugs and other invertebrates all thrive in compost. When mixed into soil, compost allows it to hold more water and nutrients. Plants respond by growing larger roots, increasing yields and even sending sugars to the roots to feed more bacteria.

Landers advises playing it safe when you’re first starting, if you’re nervous: Go light or omit oils, meats, orange peels, dairy and bones. Pet waste is a no-no. Plastic too. But don’t stress. Many prohibitions are not hard and fast rules. “A lot of the composting guidelines are built for the safest, lowest-risk situation,” she says. “Your compost bin should never keep you up at night.”

Here are the best composting operations no matter your level of commitment, or your living situation:

A 400-square-foot apartment

Anyone can collect food scraps in a bin. The main problem for urban dwellers is to find a spot for the food to break down and do its thing. They have more options now.

Hundreds of cities and private firms collect curbside composting. GreenBlue, an environmental nonprofit organization, has mapped them out. It’s a no-brainer to take advantage of these. If your city doesn’t offer compost pickup, it may have drop-off sites. To find or create a place near you, try MakeSoil, a nonprofit entity that matches people with food scraps to composting sites. If you live near one, it’s easy enough to store a few days’ worth of compost in a bin, freezer or bucket to take there. Another option: You can band together with neighbors or a community garden to start your own.

If you have easy access to off-site compost, that’s the way to go. But if you want to compost in your apartment, you have several choices.

More involved (and expensive):

There’s the emerging (almost) composting space. These are slick devices starting around $300 that process food scraps at the click of a button. Appliances like the Vitamix FoodCycler, Lomi and Mill grind up scraps and then dehydrate them. The resulting food grounds — not yet true compost since they are mostly dried-out organic matter — can be added to any garden strip or sent back to the company to be fed to livestock.

Mill’s bin, for example, fills up over the course of about three weeks for an average U.S. household. The device turns food waste into dried particles that are sent back to the company via the Postal Service for chicken feed. Membership for Mill’s service gets you all the equipment, shipping and filter refills for $33 per month.

Mill co-founder Matt Rogers, who helped launch the Nest smart thermostat, this year started to help households, and eventually cities, deal with their food waste problem. “It’s too hard to do the right thing right now,” he says. Based on an independent life cycle analysis, Mill estimates each household with its appliance prevents about half a ton of carbon emissions per year, equivalent to driving about 1,200 miles, primarily by avoiding landfills and replacing crops grown for livestock poultry. The machine uses the same amount of energy as a dishwasher — about $6 per month.

I was skeptical the energy penalty of operating the appliance would outweigh climate benefits, but Sally Brown, a soil scientist at the University of Washington who consulted with the company, says it’s still a net positive for the environment since it avoids methane emissions from landfills and crop production for poultry. “This is why I’m excited about these appliances,” says Brown. “They make it easy. You have no excuse not to use one of these.”

Except, perhaps, price. The Lomi VIP sells for about $542.

Most involved (with side benefits):

There are small vertical worm farms with several trays that fit under the sink or in a closet. Done right, they don’t smell or attract flies. You mix food scraps with some shredded paper or other brown material the worms love. Within days, the worms begin creating crumbly black soil and move upward as new food is added to each layer. You can order bags of live red wiggler worms online (imagine earthworms), and they’ll happily root around in your scraps and soil. It’s a bit of work, but some composters enjoy the process (and do-it-yourself versions exist). Your affinity for the little invertebrates will probably determine whether this is for you.

One benefit? It’s the world’s best houseplant fertilizer. “Vermicompost outdid everything,” says Brown. (More on worms later.)

Your options widen if you have outside space, even if it’s not very much.

One technique popular in the United Kingdom is the green cone digester. A perforated basket is buried a few feet underground or in a container on a hard surface. A green double-walled plastic cone sits above it. You dump in food scraps. The trapped heat from the sun and natural organisms in the soil rapidly decompose everything inside, an oxidation process that happens more slowly with true compost. This process breaks down as much as 90 percent of the volume into nutrients that migrate into the soil as they decompose, nourishing nearby plants.

You don’t get compost out of the system, but it’s an easy way to return two pounds of daily kitchen waste to the soil within an area of a few square feet — even pet waste, allegedly, according to the manufacturer, since the temperature inside can exceed 122 degrees Fahrenheit. You can buy digesters online, or through your waste authority in places like Vermont.

Another option replaces the more traditional big tumblers or plastic bins, both of which require more tending than some people might like. The Aerobin Composter, an Australian invention, essentially combines the benefits of the large plastic bin — a hot, self-contained and pest-resistant container — with an internal air conduit so compost receives enough air to keep the microbes happy. It’s insulated to trap heat and requires no mixing. Worms are optional. One with rave reviews sells for $379.99 at Costco. That’s pricey, but gardeners say the cost is quickly offset by a steady stream of rich compost, which they would otherwise buy for as much as $30 a bag.

Plus, you’ll avoid the fate of my intrepid editor, who installed two large plastic composting bins in her backyard. Her intentions were good. Each was filled to the brim with eggshells, yard waste, kitchen scraps, a Christmas tree and at least one coconut. But without the right moisture level and aeration, the microbes and worms failed to thrive. The composting process has ground to a halt. Two years later, she’s living with the equivalent of two large garbage cans.

Now she knows how to restart the process — and she has her eye on an Aerobin.

I live in a condo with a small backyard. I have a little concrete pad where I use a flow-through system called the Urban Worm Farm. It’s essentially a large canvas cone hung on a frame. You dump organic matter on top. The worms, which prefer the freshly added food, migrate up, allowing you to empty mature compost at the bottom over time.

Worms used for composting can consume about a third of their own weight daily. A farm like mine with a few thousand worms can process one or two pounds of scraps and waste per day, according to the manufacturer. About half emerges as compost.

I haven’t had a problem with smells or pests. When the mixture appeared too wet, I shredded a few paper bags and added them. The worms seemed to throw a party in their new, drier digs. Ultimately, I’ve found the little creatures, once you get to know them, are charming in their own way. Now, I can wait as long as two weeks before throwing out the trash. And the compost? Well, you should see the tomatoes I grow.


A previous version of this article misstated the first name of Sally Brown, a soil scientist at the University of Washington. She is Sally Brown, not Sarah Brown. The article has been corrected.