How to Build a Kitchen Worm Composting Box

Compost worms savor fruit waste such as cantaloupe peels.

At first glance, composting in the kitchen may seem like an impossibility, but you can make it happen quickly and inexpensively with the help of compost worms. Endowed with a hefty appetite for organic debris, these wiggly creatures eat food scraps and process them into nutrient-dense worm droppings (technically called vermicompost) that you can use as a fertilizer or for soil enrichment in your garden or backyard. Look for Eisenia fetida compost worms, also called red worms or red wigglers, in brick-and-mortar or online garden centers.

Things You'll Need

• Dark plastic storage tub with lid
• Nail and hammer or drill with ¼-inch bit
• Old newspaper and cardboard
• Water
• Eisenia fetida red worms
• Food scraps

Instructions

1. Pierce drainage holes in the bottom and sides of the plastic tub to promote air flow and keep liquid from accumulating in the worm bin. Create the drainage holes by hammering a nail into the tub or drilling openings with a ¼-inch drill bit. Make 10 to 15 drainage holes in the bottom and 25 to 30 holes in the sides of the tub.

2. Tear old newspaper and thin cardboard into 1-inch pieces and sprinkle them across the bottom of the worm composting box, filling the bottom half of the box with the bedding. Moisten the bedding material with a light mist of water, using just enough to dampen the newspaper. Stir the bedding with your hand to fluff it and increase air circulation.

3. Put your compost worms in the composting box. Use 1 lb. (about 1,000 worms) of red wiggler worms to eat up to 3 lbs. of food waste in a week. Cover the composting box loosely with the plastic lid and put it under your kitchen sink or in a dark, out-of-the-way location in your kitchen or pantry. Place the composting box on top of a plastic or metal tray to collect excess moisture that may drain from the bottom of the box.

4. Add food waste to your worm composting box once every four to seven days. Bury fruit, vegetable and mild food debris, such as banana and potato peels, overripe strawberries and stale bread, under 3 to 4 inches of the bedding; biodegradable waste, such as old napkins, paper towels, coffee grounds and tea bags also work well when added to a worm bin. Place fresh food scraps in a different corner of the composting box each time you add the waste; this gives the worms plenty of time to consume the old waste without being disturbed.

Tips & Warnings

• Select a dark plastic storage tub sized to properly process the amount of organic waste you plan to feed your worms. Allow 1 square foot of surface space for each pound of food scraps you want to put in your worm box each week; for example, if your household produces about 2 lbs. of compostable food waste per week, use a plastic tub that provides about 2 square feet of surface area, such as a 1-foot-by-2-foot container.

• Remove the brown, crumbly worm compost from your worm composting box once every eight to 10 weeks. Replace it with fresh, damp bedding for your worms and start the entire composting process over again.

• Never give dairy or meat products to your compost worms. These materials take longer to decompose and often produce bad odors that could draw rodents and insects to your worm composting box.

References

• Canada's Office of Urban Agriculture; Worm Composting; May 2011
• "The Worm Book"; Loren Nancarrow, et al.; 1998