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    How to grow shiitake mushrooms

    Lentinula edodes

    Shiitake fruits on supplemented sawdust blocks or hardwood logs at about 55–70°F, with a first harvest 7–14 weeks after spawning a block. Blocks must brown first, then a soak or cold shock starts fruiting.

    By Derick · October 24, 2026

    Fruiting temperature
    55–70°F (13–21°C)
    Humidity
    85–95% RH
    Spawn to first harvest
    About 7–14 weeks on blocks; 6–18 months on logs
    Grows on
    Supplemented hardwood sawdust blocks; hardwood logs

    Difficulty: Moderate. North Spore rates shiitake intermediate (North Spore booklet): blocks need weeks of undisturbed browning, and Cornell calls them "particularly finicky during incubation" (Cornell).

    Shiitake growing conditions at a glance

    StageTemperatureHumidityFresh air / CO2LightDays
    Spawn run and browning (block, in its bag)Under 80°F (27°C), ideally about 70°F (21°C)About 90%NoneNone required6–12 weeks, until about 75% brown
    Initiation (soak or cold shock)59–68°F (15–20°C)95%2–4 air changes an hourNatural light, or about 10 lux of 370–420 nm lightPins 7–14 days after the soak
    Fruiting59–68°F (15–20°C); 55–70°F per North Spore85–90%; 85–95% per North Spore2–4 air changes an hour; CO2 under 1,000 ppmAs for initiationFirst harvest 1–2 weeks after blocks go into fruiting
    Spawn run on logs (outdoors)Outdoor; fruiting starts once it drops to 60°F (16°C) or below60–75% for logsOutdoorsAbout 60% shade6–18 months
    Where these numbers come from
    • Spawn run. Cornell gives shiitake on sawdust 42–84 days of incubation, including 4–5 weeks after full colonization while the block popcorns and browns. It keeps incubation below 80°F, ideally around 70°F (Cornell). UC gives blocks 30–60 days at about 90% humidity, with no air exchange and no light required (UC Cooperative Extension).
    • Initiation and fruiting. The figures are UC's (UC Cooperative Extension), except the ranges marked North Spore, a kit seller (North Spore booklet). First-harvest timing comes from a farm method published by SARE (SARE).
    • Logs. Cornell gives 6–18 months (Cornell) and UC 60–75% humidity (UC Cooperative Extension). Shade and the 60°F cue are Mississippi State's (MSU Extension).

    What does shiitake grow on?

    • Supplemented hardwood sawdust

      The indoor standard: sawdust plus 10–40% starch supplements such as wheat bran, millet or rye, wetted to about 60% and sterilized 2 hours at 121°C (250°F) (Penn State). More on substrate.

    • Hardwood logs

      Fresh-cut logs 4–8 inches across and 18–36 inches long, cut while the sap is down; oak, sweetgum and beech all work. Expect 2–3 years of fruiting (MSU Extension); UC gives oak logs 3–5 (UC Cooperative Extension).

    • Hardwood fuel pellets and bran

      A home method that skips the pressure cooker: per block, 5 cups pellets, half a cup of bran and 5 cups boiling water, which semi-pasteurizes the mix (Field & Forest).

    How to grow shiitake, step by step

    1. Sterilize and inoculate

      Fill bags, sterilize them, let them cool, then mix in grain spawn. The step is done when the spawn is shaken through and each bag is sealed.

    2. Incubate undisturbed

      Space blocks a palm's width apart, or they won't popcorn where they touch (Cornell). Field & Forest, which sells spawn, incubates at 68–72°F (20–22°C); after 2–3 weeks the mycelium starts to "rope" (Field & Forest). The stage ends when the block is white and starting to bump up.

    3. Let the block brown

      The block turns bumpy, then brown. Move it on once about 75% has browned (Cornell). Field & Forest waits at least 12 weeks from inoculation (Field & Forest).

    4. Shock it into fruiting

      Chill the block in its bag, or strip it and soak it in cold water (see the soak card for times). It's done when the bare block sits on a shelf in fruiting conditions.

    5. Fruit cool and humid

      Hold 59–68°F (15–20°C) and 85–90% RH with 2–4 air changes an hour (UC Cooperative Extension). Pins should show within 7–14 days.

    6. Harvest, rest and soak again

      Pick while the cap edge is still curled under. Rest the block 8–12 days, then soak it 12 hours for the next flush (SARE).

    What's different about growing shiitake?

    Browning comes before fruiting

    Shiitake has two extra steps most species skip: after the block is white it turns bumpy ("popcorn") and then brown. Cornell warns that a drop below 55°F (13°C) after week 4 or 5, or moving the blocks, can set off early fruiting that greatly reduces yields (Cornell). Opening a block early gives small, thin caps (Field & Forest).

    Soak or cold shock: sources split on how long

    Cornell says shiitake "respond very well to shocking". It soaks blocks 5–12 hours or chills them 12–24 hours, and soaks logs 24 hours (Cornell). Other sources:

    • North Spore: fridge at least 48 hours, then a cold soak of about 4 hours (North Spore booklet).
    • Penn State: 3–4 hours in 12°C (54°F) water, harvest 9–11 days later (Penn State).
    • UC: 24–72 hours in cold water (UC Cooperative Extension).
    • Mississippi State, for logs: 12–24 hours in chilly water, mushrooms about 10 days later (MSU Extension).

    Logs or blocks

    Logs are low-tech and slow. Penn State puts the log cycle at about 6 years with efficiencies up to about 33%, against about 4 months and 75–125% for sawdust blocks (Penn State).

    When and how do you harvest shiitake?

    Pick shiitake just before the curled cap edge straightens out (UC Cooperative Extension); Mississippi State picks log mushrooms about 75% open (MSU Extension). Trim flush with the block so no stem is left before the next flush (North Spore booklet).

    North Spore expects 2–4 flushes from a block (North Spore booklet); the SARE farm method usually gets two (SARE). Between flushes, rest the block 8–12 days and soak it 12 hours. FreshCap dries blocks 2–3 weeks or more, then soaks them 24–48 hours (FreshCap). Our second-flush guide compares the methods. Logs rest 8–10 weeks between soaks, and their second and third flushes are the most productive (MSU Extension).

    UC gives shiitake a biological efficiency of 50–145% and logs an average 2–3 lb each (UC Cooperative Extension).

    Common shiitake problems

    Mushrooms forming before the block has browned

    Cold drops and moving blocks trigger early fruiting, so keep the incubation shelf steady (Cornell). When you strip the bag, pinch off and compost any premature pins (North Spore help center).

    Brown liquid in the bag

    This is normal while a block browns (Field & Forest). Brown on a shiitake block is not contamination; green, black or powdery orange spots are worth a closer look.

    Green patches on the block

    Shiitake blocks can be prone to Trichoderma (North Spore booklet). FreshCap composts a block once green mold appears (FreshCap). Our contamination guide shows how to tell it from mycelium.

    Fuzzy stems

    North Spore links fuzzy stems to too much CO2 or moisture: raise fresh air and lower humidity (North Spore booklet).

    No pins after the soak

    Check the block was mostly brown. North Spore says a too-dry block is a more common cause of no growth with shiitake, and suggests a soak or up to 24 hours in the fridge at about 40°F (4°C) (North Spore booklet). Then see why mushrooms aren't pinning.

    Tracking a shiitake grow in Hypha

    In Hypha, each block gets reminders from typical timings, including one to move it into fruiting, and you can change the dates on each block. Push that reminder out to cover the weeks a shiitake block spends browning. Log each flush as you pick it, and compare your strains' success and contamination rates over time. Download Hypha to start tracking.

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    Shiitake growing FAQ

    How long does shiitake take to grow?

    Shiitake on sawdust takes about 7–14 weeks from spawning to first harvest, or 9–17 weeks counting the grain spawn (timeline guide). Logs need 6–18 months before they fruit (Cornell).

    Can you grow shiitake indoors?

    Shiitake grows well indoors on supplemented sawdust blocks; Penn State calls sawdust the most popular base for indoor shiitake substrate (Penn State). Logs are kept outdoors in shade.

    What temperature does shiitake need?

    Shiitake blocks incubate below 80°F (27°C), ideally around 70°F (21°C) (Cornell), and fruits at 59–68°F (15–20°C) per UC (UC Cooperative Extension) or 55–70°F per North Spore (North Spore booklet).

    Is shiitake hard to grow?

    Shiitake is moderate: the steps are simple, but blocks take weeks to brown and fruit early if they're moved or chilled too soon. North Spore rates it intermediate (North Spore booklet).

    Sources

    1. North Spore booklet (cdn.shopify.com/s/files/1/2418/8179/files/FruitingBlockBooklet…)
    2. Cornell (smallfarms.cornell.edu/resources/methods-of-commercial-mushroom-culti…)
    3. UC Cooperative Extension (ucanr.edu/sites/default/files/2012-05/144812.pdf)
    4. SARE (projects.sare.org/media/pdf/F/i/t/Fitness-Farm-BLOCKS.pdf)
    5. MSU Extension (extension.msstate.edu/sites/default/files/document/2025-12/M2492_web…)
    6. Penn State (plantpath.psu.edu/about/facilities/mushroom/resources/specialty-…)
    7. Field & Forest (fieldforest.net/how-to-make-your-own-shiitake-mushroom-grow-bl…)
    8. FreshCap (freshcap.com/blogs/growing/second-flush-from-shiitake-blocks)
    9. North Spore help center (north-spore.reamaze.io/kb/troubleshooting-your-spray-and-grow-kit/whe…)

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