Earthworms are a sign of healthy soil because they aerate the soil and turn dead organic material into nutrients plants can use. As earthworms chew their way through organic material, they excrete nutrient-rich castings that, added to soil, help plants to grow and thrive. Inspired by this natural process, vermiculture, raising earthworms for their byproducts, gives way to vermicomposting, using those byproducts to enrich garden soil.
Gardeners commonly practice composting as a way to enhance soil nutrition, combining proportions of nitrogen- and carbon-rich ingredients to produce a fertile and humus-rich soil additive. However, composting takes space, and apartment and urban dwellers often lack the room for a compost heap and have further concerns with attracting vermin with food scraps or disturbing their neighbors with unpleasant smells. Because vermicomposting requires only a large box or plastic container, it is an alternative for people with little space or who wish to compost indoors.
Vermicomposting begins by providing your worms with a home to live in, which can be as simple as an old wooden crate or a plastic tub. You'll start by providing the worms with bedding to live in and feed on, such as shredded newspaper, compost, sawdust or dead plants and leaves. Vermiculture or worm farms sell red earthworms, the ideal species for vermicomposting, or you can find your own using what compost expert Barbara Pleasant calls "catch-and-release vermicomposting," catching a few dozen red worms and releasing them into your prepared worm bin. If your worm population ever grows too large, they can be returned to an outdoor compost heap. Bury food and paper scraps in the bedding, and the worms will go to work turning it into nutrient-rich compost.
Plants require nutrients to survive and are constantly drawing them from the soil, slowly depleting it of minerals. Furthermore, organic material in the soil helps it to retain water and nutrients. Earthworm castings provide both without the need to rely on synthetic plant foods. Compost from your worm bin can be used in garden plots, potted plants and container gardens. Mixing compost into potting soil or adding a layer around already established plants provides them with a nutrient boost.
In a study conducted in 1995, the U.S. Department of Agriculture estimated that 91 billion pounds of edible food was discarded as "plate waste," food unused and discarded by restaurants and consumers. Inedible food scraps--vegetable peels and rinds, for example--are also discarded, usually heading off to the nation's landfills and incinerators. In addition to supplementing the nutritional needs of your house and garden plants, vermicomposting allows your household food scraps to go to use, not go to waste.
Don't replace your trash can with a worm bin yet--not all items can be composted in a worm bin. Obvious items to avoid include plastics and metals, but greasy foods, meats, dairy, spicy and pungent vegetables and items that decompose slowly, like citrus peels, should also be avoided. Worm bins may draw gnats and flies, which indicates that you need to bury your food scraps better in an extra layer of bedding.