How to Grow Wood Ear Mushrooms (Auricularia auricula-judae)

• 1 lb dry whole wheat berries or rye berries
• Enough water to soak (cover grain by 2–3 inches)
• Large pot for simmering
• Polypropylene grain bag with 0.2–0.5 micron filter patch
• Pressure cooker capable of 15 psi

Scale-up: 3 lbs grain → 3 bags | 5 lbs grain → 5 bags

Soak the grain in cold water for 12–16 hours at room temperature to fully hydrate the kernels. Drain, then simmer in fresh water for 10–20 minutes until kernels are plump and fully hydrated but not splitting or bursting. Spread on a clean surface and allow the grain to surface dry completely — kernels should feel dry to the touch on the outside with no visible moisture, though they remain moist inside. Load the grain into polypropylene bags, filling each bag no more than two-thirds full. Fold the bag top flat and seal with an impulse sealer or fold tightly before clamping. Stand the bags upright in the pressure cooker, ensuring steam can circulate. Sterilize at 15 psi (250°F) for 90–120 minutes. Remove from heat and allow bags to cool fully to room temperature before any further handling — this takes at least 8 hours.

Out-Grow also carries sterilized grain bags ready to inoculate if you want to skip this step.

• Wood ear mushroom (Auricularia auricula-judae) liquid culture syringe — 3–5 cc per 1 lb grain bag
• Still air box or laminar flow hood
• 70% isopropyl alcohol and paper towels
• Flame source (lighter or torch)

Scale-up: 3–5 cc LC per bag regardless of batch size

Work inside a still air box or under a laminar flow hood. Wipe the self-healing injection port on each grain bag with isopropyl alcohol and let it dry for 30 seconds. Flame-sterilize the needle until glowing red, let it cool for 10 seconds, then inject 3–5 cc of wood ear mushroom (Auricularia auricula-judae) liquid culture into each 1 lb bag through the port. Withdraw the needle cleanly and wipe the port again with alcohol. Gently shake or knead each bag to distribute the liquid culture across the grain surface. Out-Grow sells wood ear mushroom (Auricularia auricula-judae) liquid culture ready to inject: Judas Ear Auricularia auricula-judae.

• Inoculated grain bags from Step 2
• Colonization space held at 73–81°F
• Darkness or very low light (below 500 lux) during spawn run

Place inoculated grain bags in a dark or dimly lit space at 73–81°F. Do not stack bags on top of each other — allow air around each bag. Shake or gently mix each bag every 4–5 days when mycelium has spread to cover at least 30% of the grain, which helps distribute colonization evenly and speeds the spawn run. Keep light levels very low during colonization — light above 500 lux can trigger premature primordia formation inside the bag. Wood ear mushroom (Auricularia auricula-judae) mycelium appears white to off-white and relatively thin and uniform, not the dense cottony growth seen in some other species. Full colonization takes 28–35 days at optimal temperature.

• 4 lbs dry hardwood sawdust (oak, beech, or mixed broadleaf; not softwood/conifer)
• 1 lb wheat bran
• 1 tbsp sucrose or plain white sugar
• 1 tbsp calcium carbonate (food-grade lime)
• Approximately 5–6 cups of water (adjust to pass squeeze test)
• Large polypropylene grow bag with 0.2–0.5 micron filter patch (XLSA or XLSB size)
• Pressure cooker capable of 15 psi

Scale-up: 3 blocks — multiply all dry ingredients by 3 and use 3 bags | 5 blocks — multiply by 5 and use 5 bags

Combine hardwood sawdust, wheat bran, sugar, and calcium carbonate in a large tub and mix dry until evenly blended. Add water gradually while mixing, stopping when the substrate passes the squeeze test: a firmly squeezed handful yields 1–2 drops from between the fingers without dripping freely. Do not exceed this moisture level — over-wet substrate creates anaerobic conditions and bacterial contamination. Load the mixed substrate into polypropylene grow bags, filling each bag no more than two-thirds full, and fold the top flat. Sterilize at 15 psi (250°F) for 90–120 minutes. Remove and allow to cool fully to room temperature — at least 8–12 hours — before inoculation.

Out-Grow also carries wood-based substrate bags ready to inoculate if you want to skip this step.

• Colonized grain spawn bags from Step 3 — 1 lb colonized grain per 5 lb substrate bag (approximately 10% spawn rate by wet weight)
• Still air box or laminar flow hood
• 70% isopropyl alcohol
• Impulse sealer

Scale-up: 1 grain bag per substrate bag, regardless of batch size

Work inside a still air box or under a laminar flow hood. Before opening, knead and squeeze the colonized grain bag vigorously until the grain separates into individual kernels with no clumps remaining — break it down fully inside the sealed bag first. Open both the grain bag and the cooled substrate bag, and distribute the colonized grain evenly across the surface of the substrate before mixing — avoid dumping all spawn into one spot. Fold the contents together thoroughly until no visible clusters of grain remain isolated from sawdust mushroom substrate. Seal the substrate bag immediately with an impulse sealer. Never inoculate substrate that is still warm.

• Inoculated substrate bags from Step 5
• Colonization space held at 73–81°F
• Darkness or very low light (below 500 lux)

Place sealed substrate bags in a dark or low-light space at 73–81°F. Do not disturb or open the bags during colonization. Keep light levels minimal — sustained light above 500 lux can trigger early primordia inside the block before it is ready. Wood ear mushroom (Auricularia auricula-judae) mycelium on sawdust mushroom substrate appears white to off-white, thinner and more uniform than many other wood-loving species, and the surface may develop a slightly glossy, compact mycelial skin at full colonization. Some bags may begin to show small, translucent gelatinous bumps under the plastic near full colonization, indicating the block is ready to fruit. Full colonization takes 28–35 days at 73–81°F.

• Fully colonized substrate blocks from Step 6
• Fruiting chamber or humidity tent capable of holding 85–95% RH
• Temperature maintained at 68–77°F
• Indirect ambient light (standard room light; not direct sunlight, not complete darkness)
• Good air exchange (fresh air exchange — FAE) — several air exchanges per hour
• Spray bottle or ultrasonic humidifier for maintaining humidity
• Sharp clean scissors or blade

Move fully colonized blocks into the fruiting environment at 68–77°F. Cut 2–4 slits approximately 1.5–2 inches long through the plastic bag surface — slits are where the wood ear mushroom (Auricularia auricula-judae) fruitbodies will emerge. Maintain relative humidity at 85–95% throughout fruiting; mist the walls and air of the chamber rather than spraying directly onto the block surface, and ensure good fresh air exchange by opening vents or fanning several times daily. Wood ear mushroom (Auricularia auricula-judae) does not require a cold shock to initiate pinning — simply cutting the slits and raising humidity to 85–95% is the fruiting trigger. Provide indirect ambient light; complete darkness produces poor or distorted ear formation. First pins — small, translucent to pale brown gelatinous nubs — typically appear within 7–14 days of cutting slits under optimal conditions.

• Clean hands or food-safe gloves
• Clean scissors or harvest knife (optional)

Harvest wood ear mushroom (Auricularia auricula-judae)s (Auricularia auricula-judae) when ears are elastic, uniformly brown to dark brown, 1.5–4 inches across, and the margins are still smooth and have not begun to curl or dry. Twist and snap each ear cleanly at its base — do not pull large sections away from the plastic or substrate, as this tears the mycelial skin and exposes the block to contamination. Ears left beyond optimal harvest become tough and leathery, margins dry and curl, and insects can appear. After harvesting all mature ears, continue misting to maintain 85–95% RH and allow the block to rest in the fruiting environment. A second flush typically appears within 7–14 days. After the second or third flush the block will shrink noticeably, the substrate will darken and appear dry, and no new primordia will form over 3–4 weeks in optimal fruiting conditions — at that point the block is spent and can be composted.

• Broadleaf hardwood logs — elder, oak, or beech; 3–5 inches in diameter; cut 4–8 weeks prior (not freshly cut, not dried out)
• Drill with 5/16 inch bit
• Grain spawn from wood ear mushroom liquid culture (produced via Method 1, Steps 1–3) — approximately 1 cup of colonized grain per 3-foot log section
• Cheese wax or beeswax, melted
• Brush for applying wax

Select logs of broadleaf hardwood cut 4–8 weeks before inoculation — the wood should still have some moisture but the natural antifungal resins in freshly cut wood should have subsided. Drill inoculation holes approximately 1 inch deep in a diamond pattern across the log, spacing holes about 6 inches apart in rows and 2 inches between rows. Pack a small amount of grain spawn firmly into each hole, ensuring full contact with the wood. Immediately seal each inoculated hole with melted cheese wax or beeswax to prevent moisture loss and contamination. Cover all cut ends of the log with wax as well.

• Inoculated logs from Step 1
• Shaded outdoor location with natural moisture (dappled shade; under trees or shade cloth)
• Garden hose or watering can for drought periods

Stack or lean inoculated logs in a shaded, moist outdoor location — under deciduous trees works well. Logs should not rest directly on soil that stays saturated; prop them slightly for drainage. During the colonization period, which takes many months, keep logs from drying out by watering during dry spells. Wood ear mushroom (Auricularia auricula-judae) fruits naturally in cool, moist conditions — autumn and wet spring seasons in most of the US. No humidity management is required outdoors. Once the log is colonized, fruitbodies will emerge from the log surface and inoculation holes in response to rain and cool temperatures. Harvest ears using the same technique as Method 1 Step 8 — twist and snap cleanly at the base.