But today, despite the popularity of backyard composting and composting pickup services, using worms at home to eat your garbage is a fringe endeavor. As my neighbor and master gardener Susan Wexler said, “Your average person isn’t going to order worms.”
Yet, earthworms can eat twice their weight per week and leave behind nutrient-rich, organic compost. Their digestive system actually enriches the waste, grinding it up and adding calcite granules and friendly bacteria. In the dirt, earthworms eat soil and organic matter and turn it into richer soil. In a home composter like mine, they can do the same with kitchen scraps, taking a mix of vegetable and fruit trimmings, along with paper and other filler, and turning it into black, sweet, earthy-smelling . . . well, worm poop.
The technical word for worm poop is castings, and the composting method is called vermiculture, or vermicomposting. Of the more than 9,000 species of earthworms, only seven have been identified as suitable for vermicomposting. Red wigglers, or Eisenia fetida, are by far the most popular choice in North America, worm experts say. They live on top of the soil in decaying organic matter — perfect for composting.
Adding castings to soil increases plant growth, according to both anecdotal evidence and scientific studies. For instance, strawberry plants with vermicompost worked into the soil had more than a third more flowers, plant runners and marketable fruit weights than plants to which only chemical fertilizer had been applied, according to a 2004 paper published online in Bioresource Technology.
I resisted creating an outdoor compost pile, both because of the smell and because we have occasional rat visitors in the yard. I know there are a wide range of enclosed outdoor composting systems. But indoor worms seemed a tidy solution. Last year, I bought a worm composter online — a set of stacking plastic trays, 14 inches square and 4½ inches deep. (I later learned it’s very easy to make a basic worm composter with a plastic bin.) I also ordered 1,000 worms from Uncle Jim’s Worm Farm, for $19.95 plus shipping. They came in a box that said “open immediately,” and inside was a pretty green cotton bag filled with my worms packed in dry peat moss.
They looked a bit dried up. But the enclosed “worm advisory” assured me they were just dehydrated for safe travel and would revive quickly.
I laid the ball of worms gently into the first plastic tray on a bedding of starter stuff (composed of coconut fiber, shredded paper and pumice) and some food scraps. I poured a half-cup of water over the worms, placed the loosefitting cover on the tray and kept a light on for the first couple of days to make sure they didn’t try to escape. But, sure enough, they seemed to disappear into the food mixture.
According to the instructions that came with the composting trays, all you need to do is to keep adding more scraps and such until the tray is full of worm castings. This can take a couple months or more. Then you put another tray on top (the tray bottom is an open grid), and add food scraps. The worms, sensing new opportunity, will migrate up to the new tray. That’s the idea.
The good news: Worm composting really does not smell.
The bad news: They are high-maintenance, at least in the beginning. They are, after all, living beings and require some care. They can’t get too hot or too cold. And it’s tricky to get the right balance of food, paper and moisture.
It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.— Charles Darwin, in "The Formation of Vegetable Mould Through the Action of Worms, With Observations on Their Habits," 1881
We put a note on the refrigerator that says: “Worms love: vegetable scraps, breads and grains, fruit rinds and petals, tea bags, coffee grounds and filters, crushed eggshells, shredded paper. Worms hate: meat or fish, cheese, butter, greasy food, animal waste, spicy and salty foods, citrus.”
The food-to-worm ratio is not precise, nor is the amount of castings they will produce. The rule of thumb is that a pound of worms will eat one to two pounds of food in a week. In the worm bin, microbes start to break down the food scraps — pre-digestion for the worms.
They prefer their food chopped up. I feel silly cutting up scraps, mixing them with shredded paper and carrying a plate downstairs to the worms. But I refuse to put the scraps in a blender, which is what a more enthusiastic family member did for a while.
But I did worry.
Sometimes clusters of worms were coming to the surface instead of burrowing, and sometimes there seemed to be lots of mites (which also contribute to the composting process but compete for food with the worms), an indication of too much moisture. I wanted to talk to other people who were worm composting at home, but when I put the word out to my very active and environmentally conscious neighborhood email group, the silence was surprising. A father and son were curious, seeing a possible school project, and a Colombian agronomist said it was a common form of composting in Colombia.
And then a neighbor told me about Jeffrey Neal.
Neal lives in a condo in the District and runs a composting operation in the basement of his building. I quickly called him up and arranged to visit. It would be my first real look at someone else’s worm bins.
He’s a retired Navy civil engineer who started composting about six years ago after one day contemplating his banana peel as he relaxed on his sofa. He said he thought about its going into a landfill: “And I just sat there: ‘Oh, just throw it away like I’ve done so many other times. No other option.’ ”
But he thought about it some more, and his banana peel was taking him to environmental problems, erosion, landfills. “It’s like in ‘The Matrix.’ I’d just taken the red pill and then I was stuck and I couldn’t go back,” he said.
He started worm composting in his apartment: “I killed my worms a couple times.” And then he took a composting course offered by the Institute for Local Self-Reliance, a national nonprofit that runs community development programs, and ECO City Farms in Prince George’s County, which runs urban farming programs. For his course project, he decided to introduce vermicomposting to his 165-unit apartment building, Rhapsody Condominiums.
He had to convince the five board members. One agreed, two were willing and the other two took more work, Neal said. Now, nearly two years into the operation, Neal and another resident of the building, Carrie Brownlie, feed the worms twice a week. The scraps come from fewer than half a dozen apartments. Neal and Brownlie did not publicize the project, preferring to start small.
We met in the lobby, took the elevator down to the trash room and retrieved a bucket of food scraps marked for composting. Brownlie and her two young sons weighed them, measured out shredded paper and mixed it all together.
In a little-used stairwell off the parking garage were 10 18-gallon plastic containers, the kind you might store offseason clothes or sports equipment in, lined up along the wall, numbered and with notes attached about the last feeding.
A thousand red wigglers weigh about a pound, and Neal estimates he has 30 pounds of worms in the 10 bins. So basically, tens of thousands of worms.
While those worms could eat 60 pounds of food scraps in a week, they do fine on a lot less, and it is more of a problem to put too much food in a bin than to underfeed them because the food will rot and build up heat, killing the worms. Neal and Brownlie add anywhere from just a few pounds to 25 pounds of food in a week.
Worms seem to do better with a bit of neglect, and skipping feeding for a few weeks is not a problem. In nature, sometimes food is plentiful, sometimes not. If you are going away for two or three weeks, you can just put extra food and shredded newspapers in the bin, and they will be fine.
Neal and Brownlie harvest castings every three or four months, a few bins at a time. In January, one bin produced 33 pounds of nutrient-rich compost.
Because they are not gardeners, they give the compost away to people in the building who have houseplants, feed the building’s roof-deck plants and save some for Neal’s mother, who lives in the suburbs. The rest goes to the nearby Howard University community garden.
Neal and Brownlie have not advertised the composting widely yet — a plan is underway to scale the operation up for the entire building this summer — so when I asked others at the Rhapsody what they thought about having worm composting in the basement, most didn’t know about it.
Learning of the close-to-home worm poop operation, they seemed unfazed, even supportive. “That’s so cool,” said Mollie Berman. “I’m not turned off by worms. I mean, there are rats in the alley. You can’t be squeamish living in the city.”
Neal has continued to study composting, going not just once but twice to the annual vermiculture conference started 18 years ago by Rhonda Sherman, extension specialist at North Carolina State University.
Sherman has a big following among worm composters, and she fields inquiries from around the world about large-scale vermicomposting. She was in the circle of recycling activists in Kalamazoo, Mich., that included the late Mary Appelhof — sometimes referred to as Worm Woman — whose "Worms Eat My Garbage" continues to be a popular reference book for home vermicomposters.
As for my own operation, after more than six months and with spring here, I’m still working on the worm routine.
I have settled on feeding them once a week, between one and two pounds of food scraps. That should yield five to eight pounds of castings every four to six months.
I recently harvested compost from the bottom tray for the first time, using the pyramid method. This involves creating small piles of compost under a light whose rays cause the worms to burrow down, and then taking off the top of the pyramid. At the end of this process, I had three-quarters of a bucket of rich black compost and a half-dozen small, wriggling knots of apparently stressed-out worms.
I added the compost to my garden, returned the worms to the bin and fed them, but they don’t seem to be burrowing very enthusiastically. I try to leave them alone, but it’s hard. They are, after all, my livestock.