What to Put in a Worm Composter

Worm composting is a way to put food waste to good use by feeding it to about a thousand worms. To return the favor, the worms provide you with a batch of rich soil amendment every two months or so. The best part is that worm bins are so small -- requiring about a square foot per pound of waste -- that you can take advantage of this process where space is at a premium, even indoors. (See References 1)

Moist Bedding

The bedding in your bin functions as the worms' home as well as part of their diet. Shredded paper works best, but use plain white paper or newspaper, not glossy or colored stock with dyes and chemicals (see References 1). Although worms live in leaves in the wild, leaves aren't suitable as bedding because they can become impacted, retain too much moisture and grow mold; or they could be contaminated by insects or chemicals (see References 2, page 14). You need 1 to 1-1/2 lbs. of bedding per square foot of surface area, and it must be moistened with triple its weight in water; this ratio ensures the proper moisture level to allow the worms to breathe (see References 2, pages 21-22). Each pound of bedding needs 3 pt. of water (see References 1).


Don't go outside and dig up earthworms for your bin -- earthworms and other garden worms need the cool, moist soil found deep underground, and will not thrive in a compost situation. Redworms (Eisenia foetida) are perfect for compost bins because they eat organic waste; putting them in a compost bin is like dropping them into a giant pile of food. Some garden centers sell redworms by the pound, or you can order them from online suppliers. Use 1 lb. of worms for every 4 square feet of bin. (See References 1)

Acceptable Waste

Think of your worms as vegetarians that will eat almost anything. Give them vegetable trimmings and scraps from meal preparation, and coffee grounds, including the filter. They will even eat used tea bags, but remove any tags and staples. Eggshells provide calcium and digestive grit for worms; crush these up before adding them to your bin. When you add fresh scraps, bury them in the bedding to avoid attracting fruit flies and encouraging mold. (See References 1, References 3, page 75)

Unacceptable Waste

Do not put meat, dairy products or fatty materials, including nut butters, in your bin; these attract pests, such as flies and rodents. Citrus products can cause acidity. Human and pet wastes are unacceptable, because they can be a source of pathogens. (See References 3, page 75).