Mushroom Farming calculators

Biological efficiency (BE) is fresh-mushroom yield as a percentage of dry substrate weight: BE % = (fresh mushroom kg ÷ dry substrate kg) × 100. Oyster mushrooms commonly reach 60–150% BE, milky 60–110%, shiitake 75–125%, while button mushrooms sit at 25–40% of compost dry weight. A 10 kg dry-straw oyster bag at 80% BE yields about 8 kg of fresh mushrooms across all flushes.

Spawn rate is usually 2–5% of wet substrate weight for oyster and milky mushrooms (so 200–500 g of grain spawn per 10 kg wet bag), about 5–8% for shiitake sawdust blocks, and roughly 0.5–1% of compost for button mushrooms. Higher spawn rates speed up colonisation and crowd out competitors but raise cost — the Mushroom Spawn Calculator works out the exact quantity and bag count.

Mushroom substrate works best around 25–30:1 C:N after composting for button mushrooms; oyster and other species are grown on higher-carbon straw (40–60:1) that is supplemented or pasteurised rather than fully composted. Too much nitrogen invites green mould and bacteria; too little starves the mycelium. The C:N Ratio and Compost Recipe calculators help you blend straw and supplements to target.

Most species fruit at high humidity (80–95% RH) with fresh-air exchange to flush CO₂. Temperature is species-specific: button 14–18 °C, shiitake 12–20 °C, oyster 20–28 °C, and milky/paddy-straw 28–35 °C. Use the Humidity & VPD Calculator to keep vapour-pressure deficit low so pins do not dry out, and the evaporative-cooling tools to hold summer rooms in range.

Oyster and milky mushrooms complete a cycle in roughly 4–8 weeks, allowing 6–10 cycles a year in a managed room; button mushrooms take 8–12 weeks (about 3–4 crops); shiitake on logs or blocks may take 3–6 months. Cycles per year is the single biggest driver of annual profit — the Mushroom Unit ROI Calculator multiplies yield per cycle by cycles to project income.

Yes — mushrooms convert low-cost agro-waste (straw, sawdust) into a crop selling at a premium, often with payback inside the first year for a small oyster unit. Profit hinges on spawn quality, biological efficiency, cycles per year and avoiding contamination losses. Run the Mushroom Unit ROI and Break-Even Yield calculators with your local spawn, substrate and market prices before investing.

Oyster mushrooms (Pleurotus) are the most forgiving: they grow on simply pasteurised straw without composting or casing, tolerate a wide 20–28 °C range, colonise fast and reach high biological efficiency. Milky mushroom suits hot climates, paddy-straw mushroom is ultra-fast but low-yield, while button and shiitake demand tighter environment control and are best attempted after oyster experience.

Contamination control rests on clean spawn, properly pasteurised or composted substrate at the right moisture, a sufficient spawn rate to colonise quickly, and a clean spawning area. The Compost Maturity & Stability Index flags under-cooked substrate that breeds green mould (Trichoderma); the Substrate Temperature Readiness tool ensures you spawn only after the substrate has cooled below the spawn's lethal temperature.

Work backwards from biological efficiency: dry substrate needed = target fresh yield ÷ BE. For 100 kg of fresh oyster mushrooms at 80% BE you need about 125 kg of dry straw (≈ 250–300 kg wet after soaking). The Mushroom Spawn Calculator handles the substrate, spawn and bag count for any target in one step.

Spent mushroom substrate (SMS) is a valuable by-product: compost it, feed it to a vermicompost bed, use it as a soil amendment or potting-mix base, or digest it for biogas. The Vermicompost Production and Biogas Plant calculators turn this waste stream into a second income line or on-farm energy.

Fresh mushrooms are highly perishable — 1–3 days at ambient but 5–10 days near 0–4 °C at high humidity. Every drop in temperature multiplies shelf life (the Q10 rule). Use the Cold Storage Shelf Life and Q10 tools to plan dispatch, or the Value-Addition Profit Calculator to convert surplus into shelf-stable dried or powdered product.

No — many growers start in a thatched hut, an insulated room, a basement or a low-cost polyhouse, as long as it holds high humidity, allows fresh-air exchange and stays in the species' temperature band. The Polyhouse / Grow-Room ROI and Evaporative Cool Chamber tools help you size a low-capital structure and keep it in range without heavy refrigeration.