Worm Composting Made Simple

Vermiculture, or worm composting, is a method for transforming food waste into nutrient-rich compost and soil conditioner. If you don’t have room for a compost pile or if you want to continue composting through the cold winter months, worm composting is a perfect solution.

If you’re not convinced that vermiculture is for you, just remember that worm composting reduces your garbage, which means there are fewer garbage trucks on the road and less need for landfills. Plus, worm composting improves your soil whether you garden in pots or in the ground. Besides being easy and fascinating, worm composting is a terrific educational project for children.

Just follow these steps to get started:

1. Container: Find or build a wood or plastic container that is eight to twelve inches high and a size you can easily move and lift. Drill eight to twelve one-quarter-inch holes in the bottom for ventilation. Raise the bin on blocks or bricks to let excess liquid run out; put a tray underneath to capture the liquid, which you can use for fertilizer. The container will need a cover to preserve moisture and keep the light out.

2. Bedding: Fill the bin three-quarters full with a variety of bedding materials such as shredded paper; chopped up leaves, straw, and plant parts; seaweed; aged manure; compost; or sawdust. And a handful each of soil and sand. Moisten the bedding so it’s as wet as a wrung-out sponge. Leave the bedding loose—don’t pack it down—to make sure there’s good air circulation.

3. Worms: Purchase red wriggler worms or collect them from a manure pile. Red wrigglers are more likely to survive than the large worms found in the soil, so stick with them. You’ll need about two pounds (2,000) of worms for every pound of food waste you plan to add each day.

Feed the worms the same types of food scraps you would put in a regular compost pile: eggs shells, tea bags, coffee grounds, and fruits and vegetables. To keep away flies, rodents, and odors, avoid fats, meats, dairy, and grains. Bury the food waste under the bedding, choosing a different spot for each feeding.

4. Location: Worm compost needs temperatures between 40 and 80 degrees F. Keep the bins out of hot sun and heavy rain. Mobile or portable bins are ideal because you can move them indoors or out when the weather changes.

5. Care: If the bin starts to give off an unpleasant odor, the bedding is too wet, probably because there’s too much food for the worms to break down quickly. Withhold food until the worms catch up. Stir the contents to increase airflow. Make sure the drainage holes aren’t clogged, and drill more holes if necessary.

If the worms start crawling out of the bedding, they’re not happy with their environment. It could be too wet or too acidic. If it’s not too wet in there cut back on citrus peels or add eggshells to reduce the acidity.

In about ten weeks the bedding will turn into compost. Separate the worms from the compost and use them to start a new bin (with a little compost mixed in with the new bedding).

6. Use: Mix your worm compost with potting soil for a rich and well-drained mix for container plants. Use it as mulch or add it to the garden soil.

Vermiculture is more popular than you might think. The following websites are among many informative sites about worms and worm composting:

Canada’s Office of Urban Agriculture encourages worm composting with a photo guide and other resources.

Find worm composting information and products from the WormWoman.

Worm Composting from the City of Vancouver.

Worm Composting Tips has a great deal of worm composting information as well.

Lynne Lamstein gardens in Maine and Florida and is currently working on a sustainable landscape. She has a degree in ornamental horticulture from Temple University.