Copyright by Jim Jensen, YELM Earthworm & Castings Farm, 1998, yelmworms@aol.com. Permission granted to copy or post with complete attribution in whole, without addition, deletion, or substitution.

Ancient cultures revered worms for the valuable role they play in the formation of rich agricultural soil. Charles Darwin observed the activity of worms and credited them with the fertility of farms the world over. For decades, worm farmers and anglers have practiced vermiculture in the pursuit of profit and recreation. Recently, however, homeowners and recycling managers have taken note of the potential of worms to help manage our "wastes."

Feeding redworms is a good way to make high-quality compost from vegetable and fruit scraps. Unlike garden earthworms or nightcrawlers, redworms (known scientifically as Eisenia fetida, or commonly as manure, striped, or brandling worms) thrive on high-organic wastes.

The use of redworms for home composting has been developing for many years and has been popularized during the past decade. Home-scale worm composting is widespread in the U.S. and Canada, and is supported by many recycling agencies and the health department.

How to Do Worm Composting

Worm composting requires four basic items: redworms, a worm bin, bedding for the worms to live in, and food scraps. Redworms thrive in a rich organic environment, with lots of decaying matter. They are capable of ingesting as much as their body weight in wastes each day. That means that for however much food scrap you generate per day, you’ll need to grow a population one to two time that weight of worms.

Researchers have found that redworms thrive in the following optimum conditions:

• temperature: 65 to 80 degrees F (15 to 25 degrees C)

• moisture content: 60 to 80 percent (higher than conventional composting)

• oxygen: yes, the worm bed must be kept aerobic

• pH: greater than 5 and less than 9

Two to three pounds of red worms will start most home worm bins. For larger scale projects, plan to start with one pound of redworms for every one to three square feet of worm bin surface area.

Give your worms a comfortable home. A good worm bin is a sturdy box with a heavy, tight-fitting lid to keep pests out and moisture in. A worm bin can be made from an old cupboard or packing crate, or built with plywood and two-by-fours. A shallow box—12 to 18 inches deep—is best because the worms live near the surface to get adequate air. Drill holes in the bottom or otherwise provide for drainage. (An idea for just trying it out: Recycle an old styrofoam chest for worm composting by poking a few holes in the sides for ventilation, and make sure that there is never any standing water in the bottom of the chest.)