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    How to grow lion's mane mushrooms

    Hericium erinaceus

    Lion's mane fruits on supplemented hardwood sawdust or logs at 55–70°F (13–21°C), with a first harvest about 3–6 weeks after spawning a bag. Keep water off the fruit and pick it before it yellows.

    By Derick · October 24, 2026

    A large lion's mane mushroom, covered in long white spines, growing from a bagged block on a counter
    Fruiting temperature
    55–70°F (13–21°C)
    Humidity
    90–95% RH to pin, 80–90% while growing
    Spawn to first harvest
    About 3–6 weeks
    Grows on
    Supplemented hardwood sawdust or hardwood logs

    Difficulty: Moderate. Lion's mane is easy to fruit from a ready-made block, but its mycelium is so fine that colonization is hard to judge, so GroCycle suggests growing oysters first (GroCycle).

    Lion's mane growing conditions at a glance

    StageTemperatureHumidityFresh air / CO2LightDays
    Bulk colonization68–75°F (20–24°C)Sealed bagNone; bag stays closedDark14–21
    Pinning55–70°F (13–21°C)90–95% RHCO2 500–700 ppm500–1,000 lux3–7
    Fruiting55–70°F (13–21°C)80–90% RHCO2 under 1,000 ppm500–1,000 lux5–10 to harvest
    Where these numbers come from
    • Colonization: GroCycle incubates the closed bag somewhere dark at 68–75°F and gives it two to three weeks (GroCycle). Cornell gives most specialty species about 21 days on sawdust (Cornell).
    • Temperature, humidity and CO2: North Spore lists 55–70°F, 90–95% to pin and 80–90% for the growing mushroom, and CO2 of 500–700 ppm to pin and under 1,000 ppm to fruit (North Spore booklet). GroCycle runs a little warmer and drier, at 59–75°F and 85–90%. The Cornell and Fungi Ally guide says lion's mane tolerates 1,000–1,300 ppm (Cornell Small Farms and Fungi Ally).
    • Light and days: GroCycle gives 500–1,000 lux, pins 3–7 days into fruiting, and mushrooms ready 5–10 days after that (GroCycle).

    None of the extension guides we checked gives lion's mane its own temperature or humidity range, so those rest on two companies that sell spawn, kits and courses: North Spore and GroCycle.

    What does lion's mane grow on?

    • Supplemented hardwood sawdust

      GroCycle's 5 lb block is five cups of hardwood pellets, 1¼ cups of bran and six cups of water (GroCycle). It needs sterilizing, not pasteurizing.

    • Hardwood logs

      GroCycle uses logs 3–10 in (8–25 cm) across. The first harvest comes one to two years after inoculation, and a log can fruit for up to six years (GroCycle).

    • Ready-to-fruit block

      A bought block skips colonization. North Spore guarantees its kits will fruit within two weeks (North Spore help center).

    How to grow lion's mane, step by step

    1. Colonize grain spawn

      Grain takes 2–3 weeks to colonize (GroCycle). Lion's mane mycelium is faint, so grain spawn is ready when no bare kernels are left, even if it looks thin.

    2. Sterilize the sawdust

      GroCycle sterilizes its bags for 2½ hours at 15 PSI and lets them cool for at least eight hours before spawning (GroCycle).

    3. Spawn and colonize the bag

      Add spawn at 5% of the wet substrate weight and keep the closed bag dark at 68–75°F for 2–3 weeks (GroCycle). Colonization is done when the mycelium has run through the whole bag, or when pins start forming inside it.

    4. Cut holes and start fruiting

      North Spore cuts 3–4 small X's on one side of the bag (North Spore booklet). Move it to 55–70°F and 90–95%. This stage is done when pins show, usually in 3–7 days.

    5. Grow the mushrooms out

      Drop humidity to 80–90% and keep CO2 under 1,000 ppm with fresh air exchange. Mist the air, not the mushrooms. North Spore says it can take about a week from pin to full maturity (North Spore help center).

    6. Harvest

      Pick when the spines are about ¼–½ in long and before any yellowing. Wrap your hand around the mushroom and twist.

    What's different about growing lion's mane?

    Mycelium so fine it looks unfinished

    North Spore calls lion's mane mycelium "notoriously fine": a healthy block can look light or almost empty next to an oyster block (North Spore help center). Judge grain by bare kernels and a bag by its days in incubation, not by how white it looks. The same fine mycelium makes blocks fall apart in a long soak.

    Keep water off the fruit

    Lion's mane soaks up water that lands on it. The Cornell and Fungi Ally guide warns that constant spraying leaves it waterlogged (Cornell Small Farms and Fungi Ally), and North Spore says it yellows when it gets too wet or too dry. Cornell side-fruits lion's mane from small cuts, because a top-fruiting block can gather water and encourage disease (Cornell).

    Fresh air and shape

    North Spore pins lion's mane at 500–700 ppm CO2, lower than its fruiting ceiling of 1,000 ppm. None of our sources describes high CO2's effect on lion's mane itself, but North Spore's booklet blames high CO2 for elongated, unusual growth in general, and notes that side fruiting can lengthen the spines (North Spore booklet). Our CO2 guide compares the sources.

    When and how do you harvest lion's mane?

    Lion's mane is ready when it comes off the bag easily; if you'd have to pull hard, wait (GroCycle). Pick before the spines turn yellow or brown. North Spore picks at ¼–½ in spines, and says a first flush from its kit can give ½–2 lb (North Spore help center).

    Expect two flushes from a block (North Spore booklet). Pins should return in about two weeks. If they don't, soak the block for only 5–10 minutes, because it can break apart (North Spore help center). Our second-flush guide compares rest and soak times.

    Common lion's mane problems

    Yellow or brown spines

    Usually age or water, not mold: North Spore links yellowing to fruit that got too wet or too dry (North Spore help center). Pick earlier and mist the air from 1–2 ft back. The contamination ID guide shows what's harmless, and our lion's mane problems guide covers pink, brown and coral fruit too.

    The bag looks barely colonized

    Faint growth is normal for lion's mane. Give it the full 2–3 weeks and check for bare substrate rather than whiteness. A block that starts pinning inside the bag is ready.

    No pins after a week in fruiting

    Give it time: GroCycle sees pins 3–7 days into fruiting (GroCycle), and North Spore guarantees its kits will fruit within two weeks. A colonized block that won't pin may be dry, so raise the humidity (North Spore help center). Our pinning guide checks fresh air and temperature too.

    Pins forming inside the bag

    Lion's mane often pins before it's exposed to air. North Spore says not to cut holes where those pins have started (North Spore booklet).

    Green patches on the block

    Green mold is usually trichoderma. Bag the block and take it out of the grow space before it spreads spores.

    Tracking a lion's mane grow in Hypha

    Hypha logs each lion's mane block from grain to harvest and sets up reminders from typical timings, including when to move it into fruiting and when each flush is due. Change any date on a block to fit your strain. Photos are organized by grow, with side-by-side comparisons, which helps when faint mycelium makes progress hard to see. Each strain's success and contamination rates show which cultures to keep.

    Get Hypha free

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    Lion's mane growing FAQ

    How long does lion's mane take to grow?

    Lion's mane takes about 3–6 weeks from spawning a bag to the first harvest, or about 5–9 weeks counting the grain spawn (timeline guide). GroCycle puts lion's mane at 4 to 6 weeks in bags and 1 to 2 years on logs (GroCycle).

    Can you grow lion's mane indoors?

    Yes. Lion's mane grows indoors in bags of sterilized sawdust, fruited in a tent or chamber. A cool basement suits it better than a warm spare room, as our fruiting temperature guide explains.

    What temperature does lion's mane need?

    Lion's mane fruits at 55–70°F (13–21°C) by North Spore's range, cooler than it colonizes. GroCycle colonizes bags at 68–75°F (20–24°C).

    Is lion's mane hard to grow?

    Lion's mane isn't hard to fruit, and North Spore rates its block for beginners. The learning curve is judging its faint mycelium and keeping water off the fruit.

    Sources

    1. GroCycle (grocycle.com/growing-lions-mane)
    2. Cornell (smallfarms.cornell.edu/resources/methods-of-commercial-mushroom-culti…)
    3. North Spore booklet (cdn.shopify.com/s/files/1/2418/8179/files/FruitingBlockBooklet…)
    4. Cornell Small Farms and Fungi Ally (projects.sare.org/media/pdf/S/p/e/Specialty_Mushroom_Farm_Book__…)
    5. North Spore help center (north-spore.reamaze.io/kb/troubleshooting-your-spray-and-grow-kit/not…)
    6. GroCycle (grocycle.com/how-to-make-grain-spawn)
    7. North Spore help center (north-spore.reamaze.io/kb/troubleshooting-your-spray-and-grow-kit/tak…)
    8. North Spore help center (north-spore.reamaze.io/kb/troubleshooting-your-spray-and-grow-kit/how…)
    9. GroCycle (grocycle.com/how-long-does-it-take-to-grow-mushrooms)

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