Worm Bins Turn Kitchen Scraps Into Compost

Brian Handwerk
for National Geographic News
September 13, 2004
For environmentally minded urbanites, no kitchen is complete without an
accessory that treats hundreds of wriggling, red guests to dinner—a
worm bin. Inside the units, worms munch kitchen scraps into rich, soil-
like humus and help reduce the amount of waste reaching landfills.

Worm composting has become so popular in Vancouver, Canada, that the city has established a telephone hot line.

So is your kitchen complete without one?

Mary Appelhof's 1982 book, Worms Eat My Garbage, spawned many a home vermicompost system and has popularized the technique over the years. The guide has now sold over 175,000 copies and earned Appelhof international recognition as the "Worm Woman."

"Here were have some of the planet's most lowly creatures taking some of our most repulsive waste and turning it into fertilizer," Appelhof said during a telephone interview. "I realized that the more worms I raised or encouraged others to raise, the world would be a better place."

A 12-inch-by-24-inch-by-20-inch (30.5-centimeter-by-61-centimeter-by-51-centimeter) worm bin can process about five pounds (2.25 kilograms) of garbage in a week.

Managing a worm bin is relatively simple. An aerated container is filled with worm bedding (shredded newspaper and dried leaves, or straw), a small amount of soil, and perhaps a pound (half a kilogram) of red worms or bloodworms.

Bacteria and other organisms break down food scraps buried in a bin maintained at proper temperature and moisture levels. Then the worms get to work, eating everything in their path—waste, organisms, and bedding. Afterward, the worms excrete a soil-like rich, dark humus.

But only certain worms can do the job.

"You can't just go out in your garden, dig up worms, and have them work," Appelhof said. "There are about 4,500 species of earthworms. Only six to eight are used for composting." One is Eisenia fetida, commonly known as a red worm.

Appelhof understands the initial reaction some people have to the idea of any worms in their kitchen. "You can almost see their nose curl up," she said.

As for odors, "there is a bit of an earthy smell," Appelhof concedes. "But when people see a well-functioning system, they are amazed at how little odor there is." (Coffee grounds and fruit and vegetable peels left in a regular trash can for several days typically smell worse, Appelhoff said.)

Not surprisingly, kids are often fond of the process and undaunted by either slime or smell. Educational outreach brings worm composting to classrooms. Appelhof estimates that nearly four million children have been introduced to worm composting through her classroom book, Worms Eat Our Garbage.

"Vermicomposting is something that kids can do. Most 18-month-olds can understand what's going on," Appelhof said. "Kids feel good [about it] because they really are doing something positive for the environment. It delights me to see them get so excited about worms."

Worms in the City

Backyard composting is easy to do, but only if you have the green space, which is why worm bins have become a popular alternative for urban dwellers.

For well over a decade the city government of Vancouver, British Columbia, has funded a worm-composting program run by City Farmer.

"I always joke that we have the largest worm program in the universe," said Michael Levenston, City Farmer's director.

Each Saturday 25 people interested in worm composting attend a one-hour workshop in City Farmer's demo garden. There, they learn how to care for and manage their worm charges. Participants leave with a bin, bedding, about a pound (half a kilogram) of red wiggler worms, and instruction books—all that's needed to put their worms to work.

"The amazing thing for us is that worms hold such an interest for the public," Levenston said. "When I watch people from all walks of life taking part in the workshops and then leave with a complete setup, it's pretty stunning. We never have a problem filling the classes. In fact, we have a waiting list."

To date the program has distributed about 3,500 worm composting bins. Each bin keeps about 130 pounds (60 kilograms) of organic waste out of city landfills each year.

Levenston says that, in addition to such tangible benefits, an entire municipal and provincial mindset of reducing waste is promoted—along with the growth of the program. "The worms are a flagship. They get people involved in trying to keep landfills smaller," he said.

Levenston recalls that, years ago, talking to the public about worm compositing "felt like I was hawking a Veg-o-Matic or something. But it's become pretty status quo to compost with a worm bin here."

These days the Vancouver program has become so widespread that it has spawned an unusual service—a compost hot line.

Worm Hot Line

Hot line operator Spring Gillard is the city's source for help on worm bins and other composting conundrums.

During 14 years on the job, she's fielded calls ranging from questions on worm sexual habits to reports of mysterious worm "wranglers"—enough material to fill a book. So that's what she did, having recently penned her Diary of a Compost Hotline Operator.

Gillard said she sometimes deals with hot line callers who are "in a panic" because their worms have escaped. "We have to talk them through this crisis and try to calm them down," she said.

Unearthing the goings on in a worm bin requires detective work, Gillard said. If your worms are "trying to escape, they are trying to tell you something," she said.

Most worms settle in nicely, and Gillard reports that most owners develop a bond with their resident trash-eaters—some perhaps a bit too much.

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