Vermicompost Production Calculator & Waste into Black Gold
Turns waste into vermicompost
Plan your vermicomposting from a waste batch — the vermicompost yield, the earthworms and bed area you need, the vermiwash you can collect, and the N-P-K it returns to your soil.
Enter your batch
Recovery is the share of feedstock weight that becomes finished vermicompost (typically 50–65%). Worms eat about half their body weight a day; ~1000 worms ≈ 1 kg.
Next: keep the bed shaded and moist (60–70%) ; harvest when the bed turns dark and crumbly. Run back-to-back for about 3,346 kg a year.
Vermicompost — key facts
- Recovery
- ≈ 50–65% of feedstock
- Worm intake
- ≈ ½ body weight/day
- Worms per kg
- ≈ 1000 individuals
- Bed loading
- ≈ 100 kg/m²
- Cycle
- ≈ 45–90 days
- Best worm
- Eisenia fetida
- Vermicompost N-P-K
- ≈ 1.6 · 1.5 · 1.5%
- Privacy
- Runs in your browser; nothing uploaded
Let worms turn your waste into fertilizer
Vermicomposting uses composting earthworms to convert crop residues, dung and kitchen waste into a fine, nutrient-rich soil conditioner — without the high temperatures of hot composting. The economics are simple to plan: about half to two-thirds of the feedstock weight ends up as finished vermicompost, the worm biomass you need scales with how fast you want the batch done, and the bed area follows a steady loading rate. This tool turns those rules into real numbers for your batch.
Beyond the compost itself you get vermiwash — a liquid feed for foliar spraying — and a known N-P-K credit you can subtract from your fertilizer bill. Keep the bed shaded, moist like a wrung-out sponge and protected from ants and birds, feed in thin layers, and harvest when it turns dark and crumbly. Pair this with the Compost & Manure and Compost C:N Ratio tools to plan the rest of your organic-matter programme.
Plan the yield
Know the vermicompost kg and bags before you start the batch.
Stock the right worms
Size the worm biomass to finish the batch in your target time.
Build the bed
Get the bed area and split large batches into manageable beds.
Bank the nutrients
Credit the N-P-K and vermiwash against your fertilizer spend.
Frequently Asked Questions
How much vermicompost will I get from organic waste?+
Typically 50–65% of the feedstock weight becomes finished vermicompost — the rest is lost as moisture and CO₂ during digestion. So 1 tonne of organic waste yields roughly 0.5–0.65 tonnes of vermicompost. This tool uses your chosen recovery rate to give the exact yield in kg and 50 kg bags.
How many worms do I need?+
Worms eat about half their body weight a day, so to process your feedstock over the cycle you need worm biomass ≈ feedstock ÷ (0.5 × cycle days). About 1000 mature worms weigh 1 kg, so the tool also gives an approximate worm count. Start with what you can and let them multiply.
How big should the vermicompost bed be?+
Beds are loaded at roughly 100 kg of feedstock per square metre at a working depth of about 30 cm. The tool sizes the bed area for your batch; for large batches it's better to split into several narrow beds (about 1 m wide) for easier handling and airflow.
Which worms are best for vermicomposting?+
Eisenia fetida (red wigglers) and Eudrilus eugeniae (African nightcrawler) are the standard composting worms — they live in the top organic layer, breed fast and tolerate handling. Deep-burrowing earthworms from the field are not suitable for bins and beds.
How long does a vermicompost cycle take?+
Usually 45–90 days depending on temperature, worm density and feedstock. Warm (25–30 °C), moist (60–70%) conditions in shade give the fastest cycles. The compost is ready when it's dark, crumbly, earthy-smelling and you can no longer recognise the original waste.
What is vermiwash?+
Vermiwash is the nutrient- and microbe-rich liquid that drains from a vermibed (or is collected by passing water through it). It's used as a foliar spray or liquid feed, diluted about 1:5 to 1:10 with water. The tool gives an approximate volume you can collect over the cycle.
What is the NPK of vermicompost?+
Finished vermicompost typically contains about 1.5–2.2% N, 1.0–1.8% P₂O₅ and 1.0–1.5% K₂O, plus micronutrients, humus and beneficial microbes. The tool estimates the total N, P and K your batch supplies so you can credit it against fertilizer.
What can I feed the worms?+
Crop residues, cow/buffalo dung, kitchen vegetable scraps, garden trimmings and partially decomposed organic matter. Avoid meat, dairy, oily food, citrus in excess, and anything with pesticides. Pre-decompose woody or fresh dung for 1–2 weeks before adding worms.
How do I keep the worms healthy?+
Keep the bed moist like a wrung-out sponge (60–70% moisture), shaded and cool, with good aeration. Avoid waterlogging, direct sun and salty or acidic feed. Protect from ants, birds and rodents. Feed in thin layers rather than dumping large amounts at once.
Is vermicompost better than ordinary compost?+
Vermicompost is generally finer, more uniform and richer in plant-available nutrients, humus and microbial life than thermophilic (hot) compost, and it's produced without high temperatures. It's an excellent soil conditioner and can cut chemical-fertilizer needs when applied regularly.