Worm Composting (Vermicomposting) Calculator
By Food Waste Amount
Calculate worm bin needs based on weekly food waste
By Household Size
Estimate worm bin needs based on number of people
Formula
Worms Needed = Weekly Food Waste (lbs) × 1,000 | Bin Area = 1 sq ft per lb of weekly waste | Compost Output ≈ 30% of input weight
Frequently Asked Questions
How many worms do I need for composting?
The rule of thumb is 1,000 worms (about 1 pound) per pound of food waste per week. A family of 4 producing 6 lbs of waste/week needs about 6,000 worms (6 lbs). Start with fewer; worms double their population every 3-6 months.
What can I feed compost worms?
Feed worms: fruit/vegetable scraps, coffee grounds and filters, tea bags, crushed eggshells, bread, and shredded paper. Avoid: meat, dairy, oily foods, citrus in large amounts, onions, garlic, and pet waste.
How long does vermicomposting take?
Worms can process food scraps into vermicompost in 3-6 months. The resulting castings are an incredibly rich fertilizer with 5x the nitrogen, 7x the phosphorus, and 11x the potassium of regular soil.
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