Composting with Worms

Reader Contribution by Felicia Rose
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Photo courtesy of Monte Larson

When my wife suggested we keep vermiculture worms in our home, my first reaction was “yuck.” I pictured thousands of worms crawling along the baseboards and walls.

“If they’re fed and watered,” she said, “they stay in the bin.” As a child, she dug worms to sell to anglers at Willard Bay. None, apparently, escaped from the peanut-butter jars or soup cans in which she kept them.

Still, the idea of bringing worms into the house unnerved me. “Can’t we keep them outside?”

“Summers are too hot,” she said, “and winters are way too cold.”

“How about the garage?”

“Still too cold.” I checked the thermometers. The one in the garage read 34 degrees Fahrenheit; the outdoor one read 6 degrees. Winters in northern Utah are like that.

I sighed. “Well, then, where were you thinking?”

“The utility room in the basement.” A hopeful smile formed on her lips. “The floors are concrete, and there’s even a floor drain.”

It sounded reasonable. Our basement is partially underground, so it remains cool when it’s hot outside. And when it’s cold, the worms would keep warm from the furnace.

“If even a single worm escapes,” I said. “They need to go.”

“It’s a deal.”

Choosing a Vermiculture Worm Bin

An hour later, we received an email confirmation saying that 2,000 red wrigglers were on their way.  

Our first task involved creating a habitat for the worms. We considered the options. Food-grade plastic bins would work, and have the advantage of not decomposing. But we prefer natural fibers, which do decompose (after all, that’s what composting is about), even though it means having to replace the bin when it rots.

Since “treated wood or any that contains a natural pest deterrent (such as cedar, redwood, and cypress) may be toxic to worms,” we avoided those as well.

In the end, we found an untreated pine bin — 44 inches long by 18 inches high by 15 inches deep — on legs at a thrift store, and decided on that. (Worms regulate their population based on the size of their space, so we weren’t concerned about their outgrowing their home.) We placed the bin in the utility room where the temperature remains within the 55- to 77-dgree range, preferable for red wrigglers.

We lined the bin with a two-inch layer of straw, half an inch of solid newspaper (no glossies), a layer of cardboard, four inches of shredded newspaper, and a handful of grit, which the worms need for digestion (they don’t have teeth).

The following week, a corrugated box arrived in the mail.

Transferring Mail-Order Worms to the Worm Bin

I donned thick cotton gloves, and then we carefully opened the box. Inside was a breathable pouch, which held oodles of worms wriggling through clumps of moist dirt. (We didn’t count them, but from the looks, all 2,000 plus quite a few offspring had reached us alive.)

My wife shook the worms into the bin and covered them with five inches of thinly-shredded newspaper pre-soaked in a bucket of water. Then she propped up the lid with a wedge to provide ventilation. Since worms prefer dark, we kept the light on for the first few days to encourage them to remain beneath the top layer of newspaper. It worked.

A week later, we lifted the newspaper to check on the worms. There they were wriggling about and eating their bedding, which they’d already begun to break down.

We began feeding them vegetable scraps (washed, so as not to introduce insect eggs into the bin), coffee grounds, coffee filters, tea leaves, teabags (minus the staples), and shredded newspaper. To keep their habitat moist, we spritzed them with water.

How to Feed Vermicomposting Worms

Over the years, we’ve continued to feed them when most of their food (not including the bedding) is gone and water them when their habitat is no longer moist. In both cases, this means about once a week.

Once a month we add grit in the form of a handful of crushed cooked eggshells, oyster shells (the same ones we feed to our hens to keep their eggshells firm) or sand. We also replenish the bedding.

No meat. No fats. No spices. No potatoes. No tomatoes. No citrus. No dairy. No salt.

We avoid flour and grains since they tend to grow moldy.

And for those who’ve asked, no french fries, marshmallows or cake.

According to the University of Oregon Extension, “When in doubt, leave it out”.

Though it would be okay to do so, we do not offer our worms fruit peels or scraps so as not to attract fruit flies. We also avoid alliums (e.g. garlic and onions) to prevent the compost bin from developing a stench.

Success on both accounts: we’ve never had a fruit fly or detected an unpleasant odor.

What we do have are 70 to 80 pounds a year of low-maintenance, nutrient-rich compost. Precious in any climate, it has proven indispensable in ours where the growing season for many plants is especially short.

Harvesting and Fertilizing with Worm Castings

We’ve experimented with starting seeds indoors both with and without castings. For large varieties of tomatoes, including Brandywines and Cherokee purples, adding worm castings to the potting soil means having the plants grow quickly enough so that the fruit ripens before the first frost. This has proven true for ground cherries and Crenshaw melons too.  

We harvest the castings twice a year, once in early spring to use for our plant starts, and then again in the fall to replenish our vegetable beds, fruit trees, and bushes.

There are several methods to harvest castings. One, referred to as hands-on, is to scoop the worms and castings onto a tarp, and then pick out the worms and return them to the bin. What remains is the compost.

Another, referred to as side-to-side, is to stop adding newspaper, water, and food to the area slated for harvest. This process encourages the worms to migrate to the side of the bin that contains nourishment and bedding. Within two or three weeks, most of the worms will have moved. Then the castings can be removed from the depleted side of the bin.

We prefer the latter method since it takes less time. I also favor it since it means not having to handle legions of worms.

Why do we practice vermiculture? One reason, already mentioned, is that the castings facilitate seed growth and add nutrients to soil and plants.

But there’s another reason too. Though we don’t grow our own coffee and tea (would that we could), we do keep chickens and grow most of our produce. By saving seed, planting that seed, giving some scraps to the chickens and some to the worms (and adding the remainder to the outdoor compost bin), we foster a closed-loop cycle on our homestead. Little in this loop comes from a store; little goes to the landfill. It supports a healthy ecosystem. It’s also fulfilling.

I lift the top layer of shredded newspaper from the left side of the bin. The worms are busy eating sunchoke scraps from their previous feeding. I add to their meal a bowlful of cooked butternut squash peels. Then I soak shredded newspaper in a bucket of water, and place it on top of the decomposing newspaper that’s already there.

In the six years we’ve kept red wrigglers, not a single worm has escaped. But even if one did, it wouldn’t be a deal breaker. I’d simply lift it bare-fingered into the bin.

Felicia Rose is a food and agriculture columnist and permaculture farmer. Shemoved from New York to a homestead in northern Utah several years ago, where she now grows and preserves tomatoes, arugula, garlic, rhubarb, and many other crops. Read all Felicia’s MOTHER EARTH NEWS postshere.

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