How to Grow Shiitake WR 50–75F Mushrooms (Lentinula edodes)

• 1 lb dry rye berries or whole wheat (yields ~2 lbs hydrated)
• Water for soaking and simmering
• Polypropylene grain bags with filter patch and self-healing injection port, or quart mason jars with modified lids
• Pressure cooker at 15 PSI

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

Rinse the rye berries under cold water until the water runs mostly clear, then submerge them fully in clean water and soak for 12–18 hours at room temperature. After soaking, drain and transfer to a pot, cover with fresh water, and simmer over medium heat for 15–20 minutes until the kernels have swollen and softened throughout but still hold their shape without splitting open. Drain immediately and spread in a thin layer on a clean towel or sheet tray. Allow the grain to surface-dry until the outsides feel dry to the touch — moist inside, dry outside. Load bags to roughly two-thirds full or fill quart jars to about three inches below the rim, then seal bags by folding and heat-sealing above the filter patch. Pressure-cook at 15 PSI for 90–120 minutes. Allow to cool completely to room temperature — this takes 4–8 hours — before touching the injection port.

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

• Shiitake WR 50–75F liquid culture syringe from Out-Grow
• Alcohol lamp or butane torch for needle sterilization
• Isopropyl alcohol (70%) wipes
• Still-air box or flow hood

Work inside a still-air box or at a flow hood. Wipe down all surfaces with 70% isopropyl alcohol. Flame-sterilize the needle until it glows red, let it cool for 10–15 seconds, then wipe with an alcohol swab. Insert the needle through the self-healing injection port and inject 3–5 cc of Shiitake WR 50–75F (Lentinula edodes) liquid culture per 1-lb bag. If using mason jars with modified lids, inject through the self-healing port in the same manner. Gently agitate the bag after injection to distribute the liquid culture throughout the grain surface. Shake or roll the bag to mix.

• Inoculated grain bags from Step 2
• Colonization space holding 68–75°F

Place inoculated bags in a dark or low-light area holding 68–75°F. Shiitake WR 50–75F mushrooms (Lentinula edodes) will colonize grain more slowly than many other species — expect 3–5 weeks to full colonization at optimal temperature. At 60–65°F the process extends noticeably; below 50°F it stalls. Shake or knead the bags once when colonization is roughly 30–40% complete to redistribute mycelium, then leave undisturbed until the grain is fully white throughout. Do not open the bags at any point during grain colonization.

• 4 lbs hardwood sawdust pellets (oak or mixed hardwood)
• ¾ lb wheat bran
• ¼ lb gypsum (calcium sulfate)
• 5½ cups water (add gradually)
• Large mixing tub
• Large mushroom grow bags with 0.2-micron filter patch
• Pressure cooker at 15 PSI

Scale-up: 3 blocks → multiply all ingredients by 3 | 5 blocks → multiply by 5

Pour the hardwood sawdust pellets into a large tub and add the wheat bran and gypsum. Mix the dry ingredients thoroughly until the bran is evenly distributed throughout the sawdust. Add the water gradually in several additions, mixing between each addition, until the substrate is uniformly moist — at field capacity, squeezing a firm handful should produce just one or two drops. If the substrate feels dry and crumbly, add water in small amounts. Load the mushroom substrate into grow bags, leaving 3–4 inches of headspace, then fold and heat-seal the bag above the filter patch. Sterilize at 15 PSI for 2.5–3 hours for large 5-lb blocks. Allow to cool completely — 8–12 hours is typical for large blocks — before opening.

Out-Grow also carries ready-to-use wood-based mushroom substrate bags if you want to skip mixing and sterilizing.

• Fully colonized grain spawn bags from Step 3 (1 lb colonized grain per 5-lb substrate block)
• Cooled and sterilized sawdust blocks from Step 4
• Still-air box or flow hood
• Isopropyl alcohol (70%) wipes

Work inside a still-air box or at a flow hood. Wipe surfaces with 70% isopropyl alcohol. Before opening, break the colonized grain spawn down fully inside the bag — squeeze and knead the exterior until all grain pieces have separated from one another and no large clumps remain. Open the grain bag and the substrate block in your clean environment. Distribute the broken grain spawn evenly across the entire surface of the mushroom substrate before mixing — avoid dumping all of it in one spot. Fold the grain into the substrate until no visible isolated clumps of grain remain unmixed. Reseal the block bag above the filter patch. The spawn rate is approximately 10–20% grain by weight relative to the substrate.

• Inoculated sawdust blocks from Step 5
• Space holding 68–75°F for colonization
• 8–12 weeks total for full colonization plus brown-film development

Place inoculated blocks in a 68–75°F environment. Shiitake WR 50–75F mushrooms (Lentinula edodes) colonize sawdust slowly — expect 4–8 weeks for the block interior to turn uniformly white. Keep bags sealed and undisturbed throughout the spawn run (colonization). Once the block is fully white throughout, maintain the same temperature for an additional 2–4 weeks while a continuous brown skin develops across the block's outer surface. This brown film (sometimes called "browning" or "skinning over") is not contamination — it is a required developmental stage that indicates the block has matured enough to fruit. Do not apply any fruiting trigger until the brown film covers most of the block surface and feels leathery or slightly firm to the touch through the bag wall.

• Fully brown-filmed shiitake (Lentinula edodes) blocks from Step 6
• Fruiting space or fruiting chamber holding 55–65°F
• Hygrometer — target 90–100% RH for the first 3–4 days of pin set
• Fresh air exchange (FAE) — CO₂ must stay below 1,200 ppm during pinning
• Ambient light — enough to read comfortably (roughly 50–100 lux)

Remove the blocks from the colonization area and transfer to a fruiting environment. For Shiitake WR 50–75F mushrooms (Lentinula edodes), drop the ambient temperature to 55–65°F — a drop of 10–20°F from colonization temperature is effective for triggering pins. Open or cut the bag to expose the brown-filmed block surface. Some growers cold-shock blocks by placing them in a 45–50°F environment for 12–24 hours first, then moving them to the fruiting space at 55–65°F. Maintain 90–100% relative humidity for the first 3–4 days by misting the walls and floor of your fruiting chamber 2–3 times daily — do not spray the block surface directly at this stage. Ensure consistent fresh air exchange: fan or vent the chamber to keep CO₂ below 1,200 ppm. Provide 50–100 lux of light for at least 8 hours per day. Shiitake WR 50–75F mushroom (Lentinula edodes) pins will appear as small, dark-tan to brown nodules emerging from the block surface within 6–14 days.

• Fruiting chamber holding 55–70°F and 85–95% RH
• Clean scissors or a sharp knife for harvesting

Once pins form, maintain 55–70°F and 85–95% RH throughout fruiting development. Reduce humidity slightly from the pin-set target as caps develop — running 90–95% RH is sufficient and reduces the risk of bacterial surface issues. Continue fresh air exchange to keep CO₂ below 1,200 ppm; elevated CO₂ during development produces long, thin stems and poor cap size. Shiitake WR 50–75F mushrooms (Lentinula edodes) typically develop from visible pins to harvest in 5–10 days at 55–65°F. Harvest when the cap margins are still slightly in-rolled and the partial veil has just broken from the cap edge — do not wait for caps to flatten fully. Cut each shiitake mushroom (Lentinula edodes) at the base of the stem using clean scissors or a knife. Twisting can pull substrate chunks from the block and slow subsequent flushes. Harvest the entire flush within a short window once caps begin maturing.

• Harvested shiitake (Lentinula edodes) block
• Clean water at 50–60°F for rehydration soak
• 10–21 days rest period between flushes

After the first harvest, remove any small pin stubs from the block surface with clean hands. Allow the block to rest in a lower-humidity environment at 55–65°F for 10–14 days. To rehydrate the block before the second flush, submerge it fully in clean water at 50–60°F for 8–12 hours, then drain and return it to fruiting conditions. Apply the same fruiting trigger protocol from Step 7 — drop temperature by 10–20°F and raise humidity to 90–100% for 3–4 days. Second flushes on Shiitake WR 50–75F mushroom (Lentinula edodes) blocks are typically smaller than the first. Blocks showing no new primordia (pinning sites) after a full rest and rehydration cycle, or blocks that are visibly light, dry, and heavily degraded in structure, have reached the end of their productive life and should be discarded.

• Fresh-cut oak or mixed hardwood logs: 6–10 inch diameter, 3–4 ft long
• Logs should be cut within the past 2–4 weeks — not dried out, not freshly cut that same day

Select logs cut from healthy oak trees — avoid softwoods such as pine and cedar, which contain resins that inhibit Shiitake WR 50–75F mushroom (Lentinula edodes) mycelial growth. Logs should be fresh enough to retain moisture in the wood but aged enough that any natural antifungal compounds in the cambium layer have dissipated — 1–3 weeks post-cut is ideal. Do not use logs with visible mold growth, signs of rot, or bark that is peeling. Cut ends should be smooth. Store logs off the ground in a shaded area until ready to inoculate.

• Power drill with 5/16-inch bit
• Colonized WR 50–75F grain spawn (from Steps 1–3 of Method 1)
• Cheese wax, melted in a small pot
• Paintbrush for wax application

Drill holes in a diamond or offset pattern along the length of each log — holes should be spaced approximately 4–6 inches apart in rows running along the grain, with each row offset by 2–3 inches laterally. Pack colonized Shiitake WR 50–75F grain spawn firmly into each hole using a dowel or inoculation tool, filling to just below the bark surface. Immediately seal each hole with melted cheese wax using a brush or dauber, covering the spawn completely to prevent drying and to block competing molds. Seal both cut ends of each log with a generous wax coat as well. Work methodically from one end of the log to the other.

• Inoculated logs from Step 2
• Shaded outdoor location with 50–70% shade
• 6–18 months colonization time depending on log diameter and ambient temperatures

Stack or lean inoculated logs off the ground in a shaded location — under a canopy of trees or beneath a shade cloth works well. Shiitake WR 50–75F mushrooms (Lentinula edodes) require log temperatures between 50–86°F during the spawn run; avoid locations where logs could exceed 86°F in summer. The WR 50–75F strain performs well in ambient temperatures that regularly dip into its lower range during spring and fall. Check log moisture regularly — logs should feel heavy and damp but not waterlogged. If logs dry out significantly during dry periods, water them by soaking for 8–12 hours or hosing them down thoroughly. A continuous white mycelium will be visible at cut ends and sometimes under loose bark after several months of active colonization.

• Fully colonized logs from Step 3
• Clean water source for soaking (if force-fruiting)
• Container large enough to fully submerge a log, or a garden hose for outdoor soaking

Shiitake WR 50–75F mushrooms (Lentinula edodes) on outdoor logs will fruit naturally when conditions enter the 50–75°F fruiting range — typically spring and fall. To force a flush at any point, fully submerge the log in cold water for 12–24 hours, then return it to its shaded resting position. This cold-water soak mimics a natural rain event and temperature drop, triggering primordia formation. Pins should appear within 6–14 days of soaking. Logs can be force-fruited every 6–8 weeks once fully colonized. Allow logs to rest at least 6–8 weeks between forced flushes to recover. During natural seasonal conditions, simply monitor for pin emergence after rains and temperature drops.

• Clean knife or scissors

Harvest each Shiitake WR 50–75F mushroom (Lentinula edodes) when the cap margin is still slightly in-rolled and the partial veil has just separated from the cap edge — do not wait for caps to flatten completely. Cut at the base of the stem with a clean knife, leaving the stub as small as possible to minimize damage to the log surface. After the flush is complete, allow the log to rest in its shaded resting position. Productive outdoor logs typically fruit for 3–5 years before yields decline significantly.