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Red wiggler worms (Eisenia fetida) can consume approximately half their body weight in food scraps per day under optimal conditions. USDA and university extension research reports a practical working rate of about one-third body weight per day. To process 1 lb of food waste per day, you need approximately 2 to 3 lb of worms (roughly 1,000 to 2,000 worms, as red wigglers weigh about 0.5 to 1 g each).

The standard recommendation from university extension services is 1 square foot of bin surface area per pound of food waste per week. A household generating 3.5 lb of food scraps per week needs at least 3.5 square feet of bin surface area. A typical starter bin is 2x2 feet (4 square feet) and can handle a 2 to 3 person household.

Red wigglers thrive on vegetable and fruit scraps, coffee grounds and filters, tea bags, eggshells, shredded non-glossy paper and cardboard. Avoid meat, fish, dairy, oily foods, citrus in large amounts, onions and garlic (which repel worms), and pet waste. USDA compost guidance and university extension services agree on these exclusions for odour and pest management.

Shredded newspaper or cardboard (no glossy ink), coconut coir, peat moss, or aged compost all work as worm bedding. Bedding should be moist (like a wrung-out sponge) and provide carbon to balance the nitrogen in food scraps. Fill the bin about two-thirds with bedding initially. Replace bedding with castings as it is consumed.

The most common method for home bins is migration harvesting: push all material to one side, add fresh food and bedding to the other side, and wait 2 to 4 weeks for worms to migrate to the new side. Then harvest the finished castings on the empty side. Worm castings are a nutrient-rich soil amendment; USDA research confirms they improve soil structure, water retention, and plant growth.