Zero Waste of Space: When opening a can of worms gives you black gold
By Juliette Fradin
Worms are a gardener’s best friend, improving the soil structure and adding nutrients. But did you know you can start worm farming, or vermiculture, right at home? This is what Carrianna Suiter-Kuruvilla did a couple months ago: “At the beginning of the pandemic, we built a few new raised garden beds, and while we compost at home, I kept reading about the benefits of the compost tea produced when vermicomposting.” So when her neighbors put their vermicomposter on the curb to give away, that was the sign she was waiting for to start!
Vermicomposting is another eco-friendly way to transform your food waste into gold for your garden, lawn and even houseplants. The worms are contained in a compost space where they live on food scraps. As the worms break down organic materials, they produce castings, which are a very high quality fertilizer. You can start vermicomposting in a small space, indoors or outdoors. Suiter-Kuruvilla set up her bin outside next to their recycling and trash cans.
And within six months, you will end up with vermicompost, also called black gold.
Red wigglers (Eisenia foetida) are the best and most widely used worms for composting. They eat a lot and reproduce very easily. European nightcrawlers (Eisenia Hortensis), are another option and are great as fishing bait, too. They can also be released into your garden.
The easiest place to find worms is right in your community. Sarah Weber, who has done vermicomposting on and off since 2011, first got some worms from a colleague: “She brought me worms in a plastic bag at work!” You may want to check out the Hyattsville email groups. Weber found a composting kit that someone was giving away on the HOPE (Hyattsville Organization for a Positive Environment) email group.
Worms breathe air through their skin, so they need a house with proper ventilation and drainage. The size of the bin you use depends on how much compost you want to produce, but the container should be between 6 and 12 inches deep. (The worms will feed in the top layers of the bedding.) You can use plastic or wood bins to make a worm box, but avoid metal containers. Reuse what you have around, like a dresser drawer, styrofoam cooler or even an old bathtub. The bin needs a cover to conserve moisture and provide darkness for the worms.
If your bin doesn’t already have holes for drainage, make about a dozen half-inch holes in the bottom of the bin, and place a plastic tray under to capture excess liquid, which you can then use as liquid plant fertilizer (more on this later). Make three to four holes on each side of the container, and cover them with a screen. Most worm bins are single-layered, but you can add another box on top so the worms can migrate up through the holes when their work is done in the first one. This allows you to collect the castings more easily.
You can install a bin indoors — in a garage, basement or kitchen, for example — but worms don’t like strong vibrations or loud sounds, so avoid the laundry room or a room with a creaky floor. Outdoors, avoid placing the bin in direct sunlight. Ideal temperatures are between 55 and 77 degrees F.
The worms need bedding to live in. Any carbon source can be used as worm bin bedding: leaves, straw, peat moss, shredded office paper, shredded cardboard, shredded newsprint (no glossy paper) and sawdust all work well. Make sure the bedding is kept as moist as a wet sponge.
What will the worms eat? Remember, they are living animals, so you cannot just feed them whatever you have on hand. They love fruits and veggies, tea, coffee grounds, mushrooms, lettuce, dead flowers, smashed eggshells, paper and cardboard, wood chips, straw and egg cartons. From time to time, you can add a handful of sand or grass clippings — but no pesticides! They don’t like citrus, garlic, leeks, bread, potatoes, dairy, meat or fat. Ideally, you should cut everything into small pieces, dig a hole in the bedding, dump the food in and cover it up with more bedding. Pick a new spot each time you add food, and don’t feed them too much all at once.
Weber and Suiter-Kuruvilla both highly recommend including your kids (or someone else’s!) in your vermicomposting activities. “That was one motivation for doing it the second time,” said Weber. “My older son was 2 at the time, and it was cool to get him interested in the process and the worms.”
Suiter-Kuruvilla purchased a kid’s book about vermicomposting to read to her kids. “My 5-year-old is really into all things animals, insects and nature right now, and I thought this would be a fun educational activity to do with him. They are pretty involved in my vegetable garden, so this has been a fun addition to bring them full circle on growing and caring for our own food.”
It will take at least six months before you can use your black gold, but after that, you can harvest more frequently. Simply dig down to the bottom of the worm bin and pull out a handful of worm castings to add directly to your soil. You can either include the worms or keep them in the bin.
Water released from the decomposing scraps in the bin will produce a black liquid called leachate, which can be nutrient-rich and useful in the garden. Dilute it (1 part leachate to 10 parts water), and use it on your indoor plants. However, refrain from using it if it smells bad, as it means bacteria could have gotten in due to overwatering and lack of oxygen. This leachate won’t benefit your plants and may, in fact, prove toxic to them.
Weber declares vermicomposting “super fun” and adds, “I highly recommend it! You don’t need anything high-tech, and there are tons of videos and instructions online on how to make your own.”