Mushroom Tools and Calculators: Grow, Forage and Cook

Which mushroom tool answers your question?

The tools on this page split by the job in front of you: growing a batch, timing a walk in the woods, cooking and storing, or reading a clue such as a spore print or a ring in the lawn. Each one takes a few numbers or choices from you and shows the math and the source behind its answer. Every tool also lists what it cannot tell you, and those limits set how far you can lean on the result. None of them can look at a mushroom, so none of them can tell you a wild one is safe to eat.

With a bucket of straw and a bag of spawn on the bench, the grow calculators turn your weights into water, lime and spawn amounts. For a free weekend and a patch of woods, the forage finders narrow down when and where to look. And when a recipe calls for fresh mushrooms but your pantry holds dried ones, the kitchen converters do the swap.

Calculators for a grow

The six grow tools follow a batch from the first mix to the harvest scale. The Substrate Calculator gives the water to add for a target moisture, and the Spawn Ratio Calculator turns a ratio such as 1:3 into litres or grams of spawn. The right moisture depends on the recipe, and one Pholiota adiposa trial compared 50, 65 and 80% water and got its best pinning and yield at 65% within its own formula. Neither tool can feel your mix, so the squeeze test still sets the last splash of water.

Spawn rate changes more than speed. For oyster mushrooms on straw, the UF/IFAS method lists 5 to 10% spawn by weight or volume without saying which total it measures against, and Cornell Small Farms notes that heavier grain inoculation of straw can raise yields. Even a higher rate never guarantees a clean tub, and the calculator cannot pick the ratio for your strain. Spawn rates for bulk substrate vary with the material, so the ratio you enter should come from the method you follow.

The straw pasteurization tool covers two routes, a cold lime soak and a hot water bath. For oyster straw in a lime soak, the Central Texas Mycological Society uses 2 g of hydrated lime per litre of water, a soak of 16 to 24 hours and a target of pH 11 or higher. The same group warns you to wear gloves, glasses and a dust mask when you handle lime. The tool works only with hydrated lime, never garden lime or quicklime, and it cannot read your pH or water temperature, so a pH strip and a thermometer still do that job.

The Grain Spawn Calculator counts your bags and gives the sterilizing time of the protocol you pick, without mixing times from different protocols. The Utah State University Extension home method pressure-cooks grain bags at about 15 psi for 120 minutes. Penn State gives 35 minutes at 121 C for a 250 mL flask of rye and 45 minutes for 1,000 mL. UF/IFAS suggests 30 minutes at 15 psi and says boiling for at least 60 minutes may not kill enough microbes, so boiled grain spawn carries a higher risk of contamination.

Your cooker is the part no calculator can check. The tool cannot tell whether your pot really reaches 15 psi, and a gauge reading does not prove the middle of the load got hot enough. It also does not replace your cooker's manual or count as canning advice.

The Grow Planner turns the day you inoculate into a dated window for each stage, and each method comes from one source that timed it. In a golden oyster trial, bags colonized fully 17 to 20 days after inoculation in darkness at 24 C. For indoor substrates such as a monotub, Cornell Small Farms gives 4 to 8 weeks of incubation, ideally at 65 to 70 F. Those dates assume the source's room, so your bag can finish early, late or not at all.

The Yield Calculator divides the fresh weight you picked by the dry weight of your substrate to give biological efficiency, or BE. Picking 1.5 kg from 2 kg of dry substrate works out to 75% BE. Your own records or your spawn supplier tell you what BE a strain should reach, and the number says nothing about income or profit.

When and where to look for wild mushrooms

Four forage tools deal with time and place, and none of them looks at the mushroom itself. The morel window by state covers 14 states, each taken from that state's own guide on this site. In the Iowa morel season, morels run from early April to mid May, and the Iowa DNR uses 53 degree soil as the cue to start looking. The dates describe a typical year and never forecast this one.

The Season Finder lists the species that fruit in a given month and region, and it marks in red the poisonous ones that fruit beside them. It only includes species whose profiles record exact months, which is a small share of the encyclopedia. Timing also shifts with rain and temperature from year to year.

The Mushrooms by Tree finder matches your host tree against the habitat lines in our profiles and lists the poisonous species first. Knowing the tree narrows the list, and the fungi on oak alone range from root partners to wood rotters, so the tree never names the mushroom in front of you. The finder also searches only our encyclopedia, which holds a fraction of the species on any tree, and a fungus on a living trunk needs an arborist's look.

The After-Rain Timer adds 2 days to the date of a soaking rain. That is the short end of the 2 to 10 days after heavy rain when mushroom activity typically rises, as Mass Audubon reports. Wood, leaf litter and lawn soak up water at different rates, so your patch may run later than the date. Larger studies such as Krah and colleagues' analysis of fruiting records tie fruiting time to temperature over the season, which is one more reason the timer gives a start day and never a deadline.

Cooking and storage converters

The kitchen tools work with shop-bought mushrooms or ones an expert has identified, never with a guess. The Measurement Converter gives a range when its sources disagree. One pound of sliced mushrooms fills about 5 cups in one published kitchen survey of sliced mushroom volume and about 6.5 cups in another chart, so the tool returns 5 to 6.5 cups. Cups measure space, so the way you slice and pack shifts the count, and the figures cover fresh button and cremini only.

The dried-to-fresh converter runs on one ratio. Reluctant Gourmet, the source of that second chart, puts one ounce of dried mushrooms in place of about eight ounces of fresh in soups, sauces and risotto. White button mushrooms hold 92.4 g of water in every 100 g, according to USDA FoodData Central, so most of their fresh weight leaves when they dry. Species that dry lighter or heavier will drift from the ratio, and Oregon State University Extension rehydrates dried pieces in boiling water when you are ready to cook.

The Shelf Life tool gives best-quality windows, and the clock starts when you put the mushrooms away. Utah State University Extension gives fresh mushrooms about five days and up to a week in the fridge, and Oregon State advises using them within a week. Cold changes the count, since UNH Extension reports 7 to 9 days at 32 to 34 F against 3 to 5 days at 36 F under commercial handling. The fridge, the paper bag and the original pack all come up in storing fresh mushrooms, and the tool cannot see how long yours sat between harvest and your kitchen.

Longer storage changes the method. Freezing mushrooms falls under the general 8 to 12 month quality range that Oregon State's freezing guide gives most frozen vegetables. Drying mushrooms keeps them for 6 to 12 months when you store them well, according to Preserve Smart.

Slime, mold or rot ends storage whatever the date says. USDA FSIS tells you to throw out moldy soft, wet produce, and trimming or sniffing it does not make it safe.

The nutrition comparison sets calories, protein, fiber, potassium, vitamin D and water side by side for raw mushrooms from USDA FoodData Central. Per 100 g, raw oyster mushrooms carry 3.31 g of protein, shiitake 2.24 g and portabella 2.11 g. Cooking drives off water and changes every figure per gram, and the tool compares food only, with no health claims.

Can a tool tell you if a mushroom is safe to eat?

No tool on this page can, and the two learning tools sit closest to that question. The Spore Print Finder lists the species in our encyclopedia that share your print color and underside type. Matching a spore print color narrows a list, but color alone cannot name a species, and the finder only knows the profiles that record a print.

The Lawn Mushroom Checker starts from the pattern the mushrooms make and what the grass is doing. UC IPM traces lawn mushrooms to buried organic matter, watering and fairy rings, and University of Illinois Extension sorts fairy rings into three symptom types that each need their own care. From there you can treat a fairy ring by its type. The checker reads one pattern at a time, cannot identify the mushroom and never calls a lawn mushroom safe to eat.

Children and dogs on the grass turn a lawn problem into a safety question. The checker gives first steps when they use the lawn, and lawn mushrooms and children covers what to do first for a toddler who may have swallowed one. If your dog may have eaten one, UC Davis School of Veterinary Medicine advises calling a vet promptly, and the steps after a dog eats a wild mushroom start with that call.