Vermicomposting is the process of composting with the use of earthworms. Vegetable and food waste is broken down by the worms, which create vermicast, or worm manure. Some organic gardeners prefer vermicompost, which is richer in nutrients than other types of compost and also contains worm mucus, which prevents nutrients from being washed away. Vermicompost promotes plant growth and creates healthy plants that better resist pests and disease. To vermicompost, you will need a source of food for the worms as well as sheltered containers to house them in.
Prepare the worm bins. You can use large plastic or styrofoam ten gallon (or larger) containers or build them out of wood. Punch three holes per square inch in the lid for aeration or, if they will be sheltered from the rain, make lids from screens or mesh. At the same time, punch or drill holes in the bottom for drainage. If vermicomposting on a larger scale, you may want to build worm beds out of concrete or wood.
Purchase the worms. Buy Red Wrigglers, which are the most commonly available kind of composting worm, and which reproduce quickly while processing large quantities of food. You can order them online or buy them from a fishing shop, which will sell them as bait worms.
Line the bins with two inches of plant material, animal manure, or a mixture of both. Put the worms in their beds. Keep the bins in a location where they will not freeze.
Feed the worms once or twice a week. Give them animal manure from an animal fed on grain; bread products; coffee filters and grounds; rinsed eggshells; fruits and vegetables, including the peel; shredded paper or cardboard; tea bags; and yard waste that has not been sprayed with pesticide. Worms eat half their body weight per day.
Stir the worms a few times once a week to make sure they are getting enough oxygen. The bin should not smell stale or rancid. If it does, you may need to discard the contents and start again.
Harvest the compost once a month, when you can see little or no trace of the food given the worms. Sort through the compost and extract as many worms as you can, but don't worry if you miss a few. Return the salvaged worms to their bins so they can create more compost.
When starting out, find out which of your gardening friends and relatives want to purchase your vermicompost. Also check with local garden clubs and stores, your local extension agent, recycling coordinators and newsletters, and large gardens. As your number of worms grows, you may sell them as well as your compost to such places or even to other vermicomposters.