How to Grow Fungi

I still remember the first flush of blue oysters breathing out anise on a cold morning, and the way the caps shed dew like tiny skylights. It hooked me for life.

“Mycelium is the earth’s natural internet.” Paul Stamets, Mycelium Running, 2005.

Fungi are neither plant nor animal, and most garden projects use saprotrophs that digest straw, wood, or composted matter. The white threadwork you see is mycelium, a living network that colonizes a substrate and later produces mushrooms.

Mycorrhizae partner with plant roots and boost nutrient flow, while saprotrophs recycle dead stuff into soil wealth. I grow saprotrophs for the plate and encourage mycorrhizae for vegetables, trees, and perennials.

• Oyster mushrooms (Pleurotus ostreatus complex): fast, forgiving, and happy on pasteurized straw or supplemented sawdust, fruiting at 55 to 75 F 13 to 24 C.
• Lion’s mane (Hericium erinaceus): crab cake texture and clean flavor, likes hardwood sawdust and steady humidity, fruiting at 60 to 70 F 16 to 21 C.
• Shiitake (Lentinula edodes): classic on oak logs with spring and fall flushes, or on supplemented sawdust blocks for speed.
• Wine cap (Stropharia rugosoannulata): carefree in outdoor wood chip beds, giant burgundy caps that pop after summer rains.

Spawn is live mycelium on a carrier, like grain or sawdust, used to inoculate a new substrate. Liquid culture is mycelium suspended in sterile broth for making your own spawn with a pressure cooker and clean technique.

• Grain spawn: fast colonization and easy mixing through straw or sawdust, typically 2 to 4 lb bags 0.9 to 1.8 kg, often 12 to 25 USD 11 to 23 EUR.
• Sawdust spawn: perfect for logs and totems, slower in loose straw, often sold in 5 lb 2.3 kg bags.
• Plug spawn: wooden dowels for log inoculation, tidy to handle, sold in packs of 100 to 1000.
• Grow kits: pre-colonized blocks that fruit in your kitchen, usually 5 to 10 lb 2.3 to 4.5 kg, often 20 to 45 USD 18 to 42 EUR.

1. Chop clean wheat straw to 1 to 3 inches 2.5 to 7.5 cm and soak it in hot water at 160 to 170 F 71 to 77 C for 1 to 2 hours to pasteurize. Drain to field capacity so a tight squeeze yields a few drops.
2. Drill 6 to 10 evenly spaced 0.5 inch 1.3 cm holes in a food grade 5 gallon 19 L bucket. Wipe the bucket and tools with 70 percent isopropyl alcohol.
3. Layer straw and grain spawn at about 10 percent spawn rate by wet weight, pressing firmly to remove air pockets. Snap the lid on and label with date and species.
4. Incubate at 68 to 75 F 20 to 24 C in the dark or low light for 10 to 14 days until white and dense. If you see green patches or sour smells, isolate and discard.
5. Move to fruiting at 60 to 68 F 16 to 20 C with 85 to 95 percent relative humidity and gentle airflow. Mist twice daily or run a humidifier and fan on timers.
6. Harvest caps when the margins flatten but before they turn up. Twist and pull the whole cluster, then chill at 34 to 38 F 1 to 3 C in a paper bag.

• Light: diffuse, like a bright room or shaded window, about 500 to 1000 lux for oysters and lion’s mane.
• Fresh air: oysters bruise into coral frills if carbon dioxide rises, so vent daily or run a small fan away from the blocks.
• Humidity: 85 to 95 percent for pinning, 80 to 90 percent for finishing, and never let surfaces crust. Fine mist beats big droplets.
• Temperature: stable beats perfect, and species vary. Check the supplier’s range for your strain.
• Cleanliness: wipe surfaces, wash hands, and keep fruiting separate from potting soil and houseplants.

Biological efficiency is yield divided by substrate dry weight. Well run oyster grows often hit 80 to 120 percent across two to three flushes.

Shiitake logs: cut dormant hardwood like oak or sugar maple 3 to 8 inches 7.5 to 20 cm in diameter, rest them 2 weeks, then drill, inoculate with plug or sawdust spawn, and seal holes with food grade wax. Stack in shade, keep moist, and expect first fruit in 6 to 18 months depending on strain and climate.

Wine cap beds: lay cardboard over soil to smother weeds, add 4 to 6 inches 10 to 15 cm of fresh hardwood chips, mix in sawdust spawn at 5 to 10 percent by volume, then top with another inch 2.5 cm of chips. Water like you would a new shrub and watch for burgundy caps after warm rains.

• Pasteurized straw: for oysters, 100 percent wheat straw at field capacity, with 1 percent gypsum by wet weight to buffer pH and add calcium sulfate.
• Supplemented sawdust: 50 percent hardwood sawdust, 30 percent hardwood fuel pellets, 20 percent wheat bran by dry weight, hydrated to 60 to 65 percent moisture, then sterilized at 15 psi 121 C 250 F for 90 to 120 minutes.
• Totem method: for oyster on logs, alternate 4 inch 10 cm cookie cuts of log with layers of sawdust spawn inside a plastic sleeve, then tie and incubate in shade.
• Coffee grounds: workable if fresh, clean, and mixed at under 30 percent with sawdust, but contamination risk runs higher than with straw or pellets.

Common signs include green patches (Trichoderma), black mold, sticky bacterial ooze, or sharp sour odors. Mycelium that stalls or turns gray often needs more air or lower humidity.

• Keep separate zones for potting soil and mushroom work, since spores from houseplants hitchhike.
• Sanitize with 70 percent alcohol, flame sterilize needles, and cool tools before touching spawn.
• Use clean water, and wipe humidifiers weekly to avoid biofilm.
• Do not baby sick blocks. Remove them before they seed the room with problems.

Work a quality mycorrhizal inoculant into planting holes for tomatoes, peppers, fruit trees, and native perennials, then keep phosphorus moderate to let the partnership thrive. Meta analyses in Ecology Letters report sizable plant growth responses in low phosphorus soils with arbuscular mycorrhizal fungi.

This is a different lane than mushrooms for the plate, yet both practices feed the soil web and improve structure, water holding, and resilience.

Pick mushrooms just before full maturity for the best texture and shelf life. Shiitake stems toughen early, while lion’s mane turns toothy and drips if you wait too long.

Store in paper at 34 to 38 F 1 to 3 C for up to a week, then cook hard and fast to drive off moisture and concentrate flavor. A heavy pan, high heat, and patience make heroes out of humble caps.

Grow only species sold as edible by reputable suppliers and avoid wild foraging unless a regional expert confirms identification. Regulations vary, so check local rules before selling produce at markets.

“Never eat wild mushrooms unless identified by an expert.” Centers for Disease Control and Prevention.

• Pressure cooker rated to 15 psi 121 C 250 F for sterilizing supplemented sawdust and tools.
• Digital hygrometer and thermometer to keep fruiting conditions steady.
• Fine mist sprayer or ultrasonic humidifier on a timer for consistent humidity.
• Drill, bit, and inoculation tool for logs, plus cheese wax or beeswax to seal.
• Nitrile gloves, 70 percent isopropyl alcohol, and clean bins with tight lids.

Choose vendors that publish strain names, preferred fruiting ranges, and production batch dates, and that ship spawn cold in warm months. Ask if they test for contaminants and back strains with performance data.

• Look for fresh spawn under 2 months old for grain and sawdust, under 6 months for plug spawn.
• Ask for biological efficiency ranges by strain and substrate so you can plan yields.
• Expect hobby kits at 20 to 45 USD 18 to 42 EUR and bulk spawn at 10 to 20 USD 9 to 19 EUR per pound 0.45 kg.

• Do mushrooms need light? Yes, a cue for pinning, but weak light works.
• Can I reuse substrate? Compost it or mulch beds and plant brassicas over it in spring.
• Why are my oysters leggy? High carbon dioxide and low fresh air.
• How cold can shiitake fruit? Some cold weather strains pop near 40 F 4 C after a soak.
• Is a HEPA filter required? Helpful for sterile work, not required for pasteurized straw projects.
• Can I grow on cardboard? Yes for wine cap and oysters as a starter, then feed with chips or straw.

Global production of mushrooms and truffles topped roughly 11 million metric tons according to FAOSTAT, with China leading output. Culinary fungi are serious agriculture, not a sideshow.

• Paul Stamets. Mycelium Running. Ten Speed Press, 2005.
• FAOSTAT. Mushrooms and truffles production statistics, latest compiled year.
• Penn State Extension. Mushroom cultivation and shiitake on logs guides, peer reviewed extension bulletins.
• Royse, N., Baars, J., Tan, Q. Current Overview of Mushroom Production in the World. In Edible and Medicinal Mushrooms, 2017.
• Hoeksema, J. et al. A meta analysis of context dependency in plant response to mycorrhizal fungi. Ecology Letters, 2010.
• CDC. Poison prevention statement on wild mushrooms, food safety communications.

Fungi reward steady hands and simple habits. Start clean. Use sterile spawn and a fit substrate for the species. Keep humidity high, not wet. Offer fresh air without gusts. Hold stable temps and soft light. Watch the mycelium like a stockpot. It will tell you when to leave it alone and when to set it to fruit.

Harvest at the veil, cut clean, and chill your pride. If green shows up, toss it and reset. Label jars, date bags, and keep notes. Save strong cultures. With patience and consistency, Fungi turn a shelf into a steady supply and your kitchen into a better place.