Consistent mushroom harvests come from consistent numbers: substrate at the right moisture, the right spawn rate, and fruiting conditions that match the species. These free tools handle the arithmetic for the most popular gourmet and medicinal mushrooms — oysters, lion’s mane, shiitake, reishi and more. Each page shows the formula and the reference data so you can see exactly where the numbers come from.

Mushroom Substrate Hydration & Spawn Rate CalculatorExact water for Master’s Mix, pellets or straw — and how much spawn to add.Mushroom Growing Conditions Chart by SpeciesTemperature, humidity & fresh-air targets for 10 gourmet species, with a live check.Mushroom Yield & Biological Efficiency CalculatorExpected harvest from your substrate and your real biological efficiency.Grain Spawn Calculator (Jars & Hydration)Dry grain to buy and water to absorb for any number of spawn jars.Pressure Cooker Sterilization Times for Mushroom Growing15 psi times for jars, bags, agar and LC — adjusted for load and altitude.Mushroom Contamination IdentifierGreen, pink, slimy or just metabolites? Identify what’s growing.Mushroom Grow Kit Finder QuizBeginner, budget and space quiz — kit, grain spawn or monotub?Mushroom Substrate Recipe Calculator (Coir / Verm / Gypsum)Scale coir / verm / gypsum to any tub — with spawn rate and water.Medicinal Mushroom Comparison (Lion’s Mane, Reishi, Cordyceps, Oyster)Lion’s mane vs reishi vs cordyceps vs oyster — grow difficulty and uses.

Where to start

New growers usually start with oyster mushrooms on straw or Master’s Mix — they’re forgiving and fast. Use the substrate hydration calculator when you mix a batch, check the grow conditions chart before you move blocks to fruit, and log your harvests in the yield calculator to see whether a change in method actually improved your results.

Have a species or substrate you’d like added? Tell us.