Like diners everywhere, the bacteria and fungi in a regular compost pile, as well as the more complex red wigglers in a worm bins, have their eating preferences. So do noxious rodents, leading to certain items that you need to exclude from a home compost system. Whether you pursue regular composting or the worm bin variation, you can master the go and no-go lists of what food scraps to compost.
Leftover vegetable materials form the bulk of food scraps that you can compost. These can include base and leafy tops of chopped celery, turnips, cabbage or heads of lettuce; the woody part of broccoli stem; as well as carrot peelings, apple skins and cores, wheat grass roots, the pulp of carrots or tomato, pineapple and rind, potatoes and potato salad, and cucumber skins or tops. Wilted salad components work well. Banana peels are OK if washed first to remove pesticides typically applied to the stem area to ward off fruit flies. Citrus peels decompose slowly but will work in a regular compost bin; they can make a worm bin too acidic.
A demonstration worm bin project in Kalamazoo, Michigan, described by biologist Mary Appelhof in "Worms Eat My Garbage," noted the successful composting of vegetable scraps and grain products as well. The list included baked beans, biscuits, cake, cereal, corn bread, cream of wheat, farina, grits, molasses, oatmeal, pancakes and pizza crust. Brewed tea leaves and coffee grounds also compost well.
Treats for Worms
Eggshells, crushed with a rolling pin, provide grist for worm gizzards and reduces the size of the shell fragments for their tiny mouths. Your worm herd may especially devour sweet scraps such as rinds of watermelon or cantaloupe and moldy strawberries. Discarded Halloween pumpkins, chopped, frozen and thawed in gradual portions, attract worm especially. "For curiosity's sake, you might want to note their preference," writes Appelhof in "Worms Eat My Garbage," noting her worm herd's predilection for watermelon rind, as well as pumpkin and squash. Spoiled powdered milk also disappears quickly if sprinkled on top of their bedding.
Composting can provide a rich learning experience if children or students observe worm preferences. Even a 3-year-old can understand the concept, asking, "Mommy, do I throw this in the garbage can or do I feed it to the worms?" Appelhof writes.
On the "no good" list for home composting are meat, poultry and fish scraps and bones, cheese, oily foods, butter and other animal products. The goal is to avoid attracting rodents and pets to the compost pile or worm bin. Despite this warning, the Kalamazoo demonstration project successfully composted both cheese and deviled eggs, and Appelhof notes successful composting of cheese in indoor worm systems, where attracting rodents is not a problem.
- "Worms Eat My Garbage"; Mary Appelhof; 1982
- King County (Washington): Backyard Food Composting; July 13, 2010
- CalRecycle; Food Scrap Management: Frequently Asked Questions; March 15, 2011
- Photo Credit Martin Poole/Digital Vision/Getty Images