How to Grow Reishi Mushrooms (Ganoderma lucidum)
How to Grow Reishi Mushrooms (Ganoderma lucidum)
Reishi mushrooms (Ganoderma lucidum) are grown by inoculating sterilized grain with a liquid culture syringe, then mixing that colonized grain spawn into a supplemented hardwood sawdust block and fruiting at 68–77°F with relative humidity held at 85–95% for the 30–60 days it takes conks to mature. Unlike oyster mushrooms or shiitake, reishi (Ganoderma lucidum) will not automatically form conks — your CO2 levels and air exchange rate directly determine whether you grow flat shelf-like conks or long sterile antlers, making environmental control the single most important skill in this grow.
Reishi Mushroom Equipment — Sterilized Sawdust Block Method
| Item | Spec / Notes |
|---|---|
| Reishi liquid culture syringe | Out-Grow Ganoderma lucidum liquid culture syringe; 10–12 cc per quart grain jar |
| Sterilized grain bags | 1 lb bags with 0.2-micron filter patch and self-healing injection port; rye, wheat berry, or millet |
| Hardwood sawdust or fuel pellets | Oak, maple, or beech; avoid resinous softwoods |
| Soy hull pellets | Available at farm feed stores; 20% of dry mushroom substrate by weight |
| Wheat bran | 20% of dry mushroom substrate by weight; do not exceed 25% total supplementation |
| Mushroom grow bags with filter patch | Polypropylene bags rated for autoclave sterilization |
| Pressure cooker or autoclave | Must reach 250°F (15 PSI) for sterilization; 23-quart minimum for 1 lb bags |
| Impulse sealer | For sealing unfilled grow bags; Out-Grow grain bags use injection ports — no sealer needed for those |
| Still air box or flow hood | Contamination-free workspace for inoculation |
| 70% isopropyl alcohol | Wipe syringes, gloves, and work surfaces before inoculation |
| Thermometer / hygrometer | Digital preferred; needed to hold colonization and fruiting temps accurately |
| Humidity tent or fruiting chamber | Maintains 85–95% RH during the long fruiting window |
| Spray bottle | Misting for surface humidity; do not spray fruiting bodies directly |
| Clean knife or scalpel | For harvesting conks at the base |
Reishi Mushrooms: Sterilized Sawdust Block Method
- 1 lb dry rye berries, wheat berries, or millet (yields ~1 lb colonized grain spawn)
- Water for soaking and simmering
- Large pot
- Colander
- 1 lb sterilized grain bag with 0.2-micron filter patch and self-healing injection port, or mason jars with modified lids
- Pressure cooker reaching 250°F at 15 PSI
Rinse the grain under cold water until the water runs clear, then soak it in a large pot of cold water for 12–18 hours at room temperature. After soaking, drain and transfer the grain to a pot of fresh water. Bring it to a boil and simmer for 10–20 minutes until each kernel is fully hydrated but still holds its shape — a kernel should give when pressed but not burst. Drain thoroughly and spread the grain on a clean surface for 15–20 minutes to surface-dry; excess surface moisture invites bacterial contamination. Fill your grain bags or jars about two-thirds full, leaving headspace for gas exchange. If using bags with a self-healing injection port and 0.2-micron filter patch, no impulse-sealing is required — the port handles inoculation and the filter handles gas exchange. Load the filled bags into your pressure cooker and sterilize at 250°F (15 PSI) for 90–120 minutes. Allow the pressure cooker to return to ambient pressure on its own — never force-release steam. Let the bags cool to room temperature, 70–75°F, before moving to inoculation.
- Out-Grow Reishi (Ganoderma lucidum) liquid culture syringe
- Cooled sterilized grain bags from Step 1
- 70% isopropyl alcohol and paper towels
- Still air box or flow hood
- Nitrile gloves
Set up your still air box or flow hood and wipe the entire interior with 70% isopropyl alcohol. Put on nitrile gloves and wipe them with alcohol as well. Shake your reishi (Ganoderma lucidum) liquid culture syringe vigorously for 10–15 seconds to break up any mycelial clumps and distribute the culture evenly. Flame-sterilize the needle tip until red-hot, let it cool for several seconds, then wipe with an alcohol-dampened cloth. Inject 2–4 cc of liquid culture directly through the self-healing injection port of each grain bag. After injection, give the bag a gentle shake to distribute the culture across the grain surface. Repeat for each bag, re-flaming the needle between bags. Place the inoculated bags in a warm, dark location at 75–81°F for colonization — a shelf in a heated room away from direct sunlight works well.
- 4 lbs hardwood sawdust or hardwood fuel pellets (oak, maple, or beech)
- 1.3 lbs soy hull pellets
- 1.3 lbs wheat bran
- Water to reach 60–67% moisture content
- Large mixing tub
- Mushroom grow bag rated for autoclave sterilization
- Impulse sealer (if bag has no filter patch)
- Pressure cooker reaching 250°F at 15 PSI
If using hardwood fuel pellets, add water gradually and allow them to fully hydrate and break apart into sawdust before mixing in other ingredients. Combine the hydrated sawdust, soy hull pellets, and wheat bran in a large tub and mix thoroughly until the ingredients are evenly distributed. The mushroom substrate is at correct moisture when you can squeeze a handful firmly and only a few drops of water emerge — if water streams out, the mushroom substrate is too wet. Fill the grow bag, press out air pockets, and seal the top with an impulse sealer or fold it over securely. Sterilize at 250°F (15 PSI) for 90–120 minutes in your pressure cooker. Let pressure drop naturally, then allow bags to cool completely to room temperature, typically 12–18 hours, before moving to grain spawn mixing. Do not open bags or proceed while any warmth remains — residual heat above 75°F will kill your reishi (Ganoderma lucidum) mycelium on contact.
If you prefer to skip the sterilization step, Out-Grow's Wood-Based All-in-One Mushroom Grow Bag is a ready-to-inoculate alternative that ships sterilized and ready for grain spawn mixing.
Ready to start growing? Out-Grow carries a liquid culture for this species.
Start with this culture — Ganoderma lucidum- Fully colonized grain bags from Step 2
- Sterilized, cooled sawdust blocks from Step 3
- Still air box or flow hood
- 70% isopropyl alcohol and nitrile gloves
Work inside your still air box or flow hood with freshly alcohol-wiped gloves. Open the grain bag and break up any clumps by squeezing from the outside before opening — this distributes the grain spawn points evenly. Open the mushroom substrate bag, pour the colonized grain directly into the sawdust block, and mix thoroughly by massaging the outside of the closed bag until grain spawn is evenly distributed throughout. You are targeting a grain spawn rate of 5–10% of the wet mushroom substrate weight — one 1 lb bag of colonized grain per 5 lb sawdust block is well within this range. Once mixed, fold the top of the grow bag down tightly, seal if needed, and return the bag to the warm, dark location used in Step 2. Colonization of the sawdust block takes 14–28 days at 75–81°F. Reishi (Ganoderma lucidum) mycelium will first appear as patches of bright white growth, gradually thickening into a dense, cottony mat and eventually forming a firm, leathery white rind across the entire block surface.
- Fully colonized reishi sawdust block from Step 4
- Fruiting chamber or humidity tent maintaining 85–95% RH
- Thermometer / hygrometer
- Diffuse light source — 12 hours per day (indirect sunlight or a simple grow light on a timer)
- Spray bottle for ambient misting
Cut or fold open the top of the block bag to expose the colonized surface to fresh air. Move the block into your fruiting chamber and set the temperature to 68–77°F — slightly cooler than the colonization temperature encourages fruiting. Maintain relative humidity at 85–95% through regular misting of the chamber walls and floor, not the block itself; direct misting of the exposed surface can cause bacterial spots. Provide 12 hours of diffuse light per day — reishi (Ganoderma lucidum) requires light to develop normal conk morphology. Fresh air exchange is critical at this stage: air out the chamber at least twice daily by fanning with the lid open for 1–2 minutes. Within 7–14 days you will see small white-to-yellowish knobs emerging from the block surface, quickly elongating into smooth antler-like fingers. Whether those antlers expand into flat, varnished conks depends on your air exchange — more fresh air at this stage encourages the wide fan-shaped conks that are the characteristic form of reishi (Ganoderma lucidum).
- Fruiting chamber with stable 68–77°F temperature and 85–95% RH
- Diffuse light on 12-hour timer
- Spray bottle
- Patience — reishi mushrooms (Ganoderma lucidum) take 30–60 days from first pins to harvest
Continue misting the chamber walls once or twice daily to maintain humidity, and fan the chamber for fresh air exchange at least twice daily. Avoid spraying the growing conks directly — the caps are sensitive to water spots and direct moisture can cause cracking or deformity. Reishi mushrooms (Ganoderma lucidum) grow very slowly compared to other cultivated species; expect the conks to add visible size week by week rather than overnight. As the caps grow they will pass through white, yellow, and orange phases before settling into a deep reddish-brown with a lacquered, varnish-like surface — this is normal and expected. Keep temperature stable within the 68–77°F band; temperature swings combined with low humidity are the primary cause of cracked or misshapen reishi (Ganoderma lucidum) conks.
- Clean knife or scalpel
- 70% isopropyl alcohol for wiping the blade
- Tray or bag for collecting harvested reishi (Ganoderma lucidum) conks
Harvest reishi mushrooms (Ganoderma lucidum) by cutting the conk at its base with a clean, alcohol-wiped knife — do not twist or pull, as this can tear chunks from the block and create wounds prone to contamination. The correct harvest time is when the white growing margin shrinks to less than roughly half an inch wide and the full cap surface has developed its characteristic deep reddish-brown varnish. Harvesting on time is important: over-mature reishi (Ganoderma lucidum) will release a heavy cloud of brown spores that coats everything in your grow space. After cutting, the block may produce a secondary flush with smaller conks; leave the block in fruiting conditions for 2–4 more weeks and maintain humidity to encourage regrowth. Most reishi (Ganoderma lucidum) blocks grown indoors on sawdust produce one primary flush with a biological efficiency of 10–35% — a 5 lb block yielding approximately 0.5–1.5 lbs of fresh conks. Dry harvested reishi (Ganoderma lucidum) at 95–140°F in a food dehydrator for 8–24 hours until fully brittle for long-term storage.
Reishi Mushroom Equipment — Outdoor Log Method
| Item | Spec / Notes |
|---|---|
| Reishi liquid culture syringe | Out-Grow Ganoderma lucidum liquid culture syringe; used to inoculate grain for sawdust plug spawn |
| Hardwood logs | Oak, maple, or beech; 4–6 inches diameter, 12–20 inches long; cut within the past 2–4 weeks |
| Hardwood sawdust plug spawn | Prepared from colonized grain mixed into hardwood sawdust, packed into dowel-sized plugs |
| Drill with 5/16-inch bit | For drilling inoculation holes 1 inch deep |
| Rubber mallet or hammer | For driving plug spawn into holes |
| Cheese wax or beeswax | Seals holes after inoculation to prevent drying and contamination |
| Propane torch or double boiler | For melting wax |
| Shaded outdoor location | 50–80% shade; protected from direct sun and drying winds |
Reishi Mushrooms: Outdoor Log Method
- Fresh-cut hardwood logs — oak, maple, or beech; 4–6 inches in diameter, 12–20 inches long
- Logs should be cut no more than 2–4 weeks before inoculation; older logs dry out too much or harbor competing fungi
Select logs from healthy, living hardwood trees — avoid logs from trees that were diseased, dead standing for extended periods, or showing signs of existing fungal colonization. Cut logs to the 12–20 inch length range and allow them to rest in a shaded, protected spot for 1–2 weeks if freshly cut, to let any natural antimicrobial compounds in the sap wood dissipate. Do not soak or wet the logs before inoculation; natural moisture content in freshly cut wood is sufficient. Logs must be inoculated before they dry out — aim to complete the inoculation within 4 weeks of cutting.
- Prepared hardwood logs
- Reishi mushroom (Ganoderma lucidum) sawdust plug spawn (prepared from colonized grain and sawdust, or purchased ready-made)
- Drill with 5/16-inch bit
- Rubber mallet
- Melted cheese wax or beeswax in a small container
- Foam brush for applying wax
Drill holes 1 inch deep every 4–6 inches along the length of the log in a diamond or offset pattern, spacing rows about 2–2.5 inches apart. This pattern ensures thorough colonization throughout the log. Pack plug spawn firmly into each hole using a rubber mallet, pressing until the plug sits flush with the log surface. Once all holes are filled, immediately seal each hole with melted cheese wax or beeswax — use a foam brush to dab a thick coat over each plug. The wax prevents the plugs from drying out and blocks competing molds from entering. Seal the cut ends of each log with a heavy coat of wax as well.
- Shaded outdoor location with 50–80% shade — under a canopy, deciduous trees, or shade cloth
- Garden hose or watering can
- 6–18 months of patience — reishi mushrooms (Ganoderma lucidum) colonize logs slowly
Stack or lean the inoculated logs in a shaded, protected spot where they will receive occasional natural rainfall. Arrange them so air circulates around each log but direct sun does not reach the bark. Reishi mushrooms (Ganoderma lucidum) need the equivalent of about 1 inch of rain per week during the colonization period — in dry climates or drought conditions, water the logs manually to maintain consistent moisture. Do not allow logs to dry out completely between waterings; check that the bark surface is cool and slightly damp when touched. Colonization takes 6–18 months depending on log diameter, temperature, and the time of year inoculation was done — larger logs on the cooler end of that range. You will know colonization is progressing when white mycelial growth becomes visible in the drilled holes or under the bark edge.
- Fully colonized logs from Step 3
- Warm, wet weather — outdoor log reishi (Ganoderma lucidum) fruits naturally during warm, humid seasons
- Garden hose for supplemental watering in dry conditions
- Clean knife for harvesting
Reishi mushrooms (Ganoderma lucidum) on logs fruit naturally when outdoor temperatures are in the 60–82°F range and humidity is elevated — this usually means late spring through early fall in most US climates. In drier periods, water the logs more frequently to simulate rain and encourage fruiting. Once conks begin to form, maintain moisture around the logs but do not water the conks directly. Harvest timing is the same as the block method: cut conks at the base when the white growing margin shrinks to less than half an inch wide and the full cap surface has developed a deep reddish-brown lacquer. A well-colonized hardwood log can fruit reishi (Ganoderma lucidum) for several years before the wood is exhausted.
Reishi Mushroom Troubleshooting — Common Problems
The most common reason reishi mushroom (Ganoderma lucidum) blocks fail to produce recognizable conks is inadequate fresh air exchange during fruiting. Reishi (Ganoderma lucidum) is extremely sensitive to elevated CO2 — when carbon dioxide accumulates inside a closed tent or chamber, the mushrooms respond by growing long, finger-like antlers that never develop into the flat, lacquered conks most growers are after. If your reishi (Ganoderma lucidum) block is producing only thin antlers that grow upward but never widen, increase your fresh air exchange immediately by fanning the chamber more frequently and ensuring adequate ventilation. At the same time, raise relative humidity to 90–95% — antler-only morphology is often a combination of high CO2 and slightly low humidity rather than either alone. Once antlers reach 2–3 inches, increasing fresh air and light exposure will push the growth toward the wider conk form.
Contamination in reishi mushroom (Ganoderma lucidum) grows almost always traces back to insufficient sterilization or mushroom substrate that was too wet when packed. Green powdery patches on a colonizing block indicate Trichoderma mold — the most aggressive competitor in supplemented sawdust mushroom substrates. Trichoderma is very difficult to reverse once established; blocks with significant green contamination should be removed from the grow space immediately to prevent spore spread. Prevent it in future batches by sterilizing at 250°F for a full 90–120 minutes and by keeping supplementation at or below 20–25% of dry mushroom substrate weight. Bacterial contamination, recognizable as slimy, wet-looking areas with a sour or rotten odor, usually means the mushroom substrate was packed at moisture above 67% or that inoculation technique was not fully sterile. Discard affected bags and reduce water content in the next batch — the squeeze test should produce only a few drops, not a stream.
Slow or stalled colonization with thin, wispy mycelium that never thickens into reishi's characteristic white rind usually points to weak liquid culture, a colonization temperature below 75°F, or a grain spawn rate below 5% of wet mushroom substrate weight. Reishi mushroom (Ganoderma lucidum) mycelium is slow-growing compared to oyster or shiitake even under ideal conditions — 14–28 days to full colonization of a 5 lb block is normal. If a block shows no visible progress after 10–14 days at the correct temperature, the liquid culture may have lost viability or the inoculation rate was too low. Pinning failures on fully colonized blocks — where the block looks healthy but produces no primordia — are almost always caused by humidity below 85% or inadequate light. Reishi (Ganoderma lucidum) needs both high humidity and consistent diffuse light to initiate fruiting; running a 12-hour light schedule and maintaining 90–95% RH during the first two weeks after moving to fruiting conditions resolves most stalled-block situations.
Get everything you need to grow at Out-Grow.
Shop mushroom substrate at Out-Grow.How to Grow Ganoderma lucidum
Questions and Answers About Ganoderma lucidum Cultivation
Q. How long does it take to grow reishi mushrooms (Ganoderma lucidum) from liquid culture to harvest?
A. From inoculating grain with liquid culture to harvesting your first conks, expect 10–16 weeks total. Grain colonization takes 2–4 weeks, sawdust block colonization another 2–4 weeks, and then fruiting and conk development takes 30–60 days from the first visible pins. Reishi mushrooms (Ganoderma lucidum) are one of the slowest-fruiting cultivated species — plan accordingly and do not judge the grow by the timeline of faster gourmet mushrooms.
Q. Why are my reishi mushrooms (Ganoderma lucidum) only growing antlers and not flat conks?
A. Antler morphology in reishi (Ganoderma lucidum) is a direct response to elevated CO2 and insufficient fresh air exchange. Increase ventilation by fanning your fruiting chamber more frequently and ensuring the grow space has adequate airflow. At the same time, provide consistent diffuse light on a 12-hour cycle — both fresh air and light are required for reishi (Ganoderma lucidum) to develop its characteristic flat, shelf-like conks rather than elongated sterile antlers.
Q. When should I harvest reishi mushrooms (Ganoderma lucidum)?
A. Harvest reishi mushrooms (Ganoderma lucidum) when the white or cream-colored growing margin at the edge of the conk has narrowed to less than roughly half an inch wide and the full cap surface has developed a deep reddish-brown lacquer. If you wait too long, the conk will release a large cloud of brown spores that coats your entire grow space. Use a clean knife to cut the conk at its base — never twist or pull, as this damages the block and invites contamination.
Q. What mushroom substrate is best for growing reishi mushrooms (Ganoderma lucidum) indoors?
A. The most reliable indoor mushroom substrate for reishi mushrooms (Ganoderma lucidum) is a supplemented hardwood sawdust block made from 60% hardwood sawdust or fuel pellets, 20% soy hulls, and 20% wheat bran by dry weight, hydrated to 60–67% moisture content and sterilized at 250°F for 90–120 minutes. Avoid pure straw without supplementation, which gives poor results for reishi (Ganoderma lucidum), and avoid supplementation above 25% of total dry weight, which increases contamination risk significantly.
Q. How many flushes can I get from a reishi mushroom (Ganoderma lucidum) block?
A. Most indoor reishi mushroom (Ganoderma lucidum) blocks produce one primary flush with a biological efficiency of roughly 10–35%, yielding approximately 0.5–1.5 lbs of fresh conks from a 5 lb block. A second, smaller flush may appear if you leave the block in fruiting conditions for 2–4 weeks after the first harvest — maintain humidity and check for new white mycelial growth as the indicator. Unlike oyster mushrooms or shiitake, reishi (Ganoderma lucidum) rarely produces multiple distinct, high-yielding flushes from a single indoor block.
Q. What temperature does reishi (Ganoderma lucidum) need for colonization versus fruiting?
A. Reishi mushroom (Ganoderma lucidum) mycelium colonizes grain and sawdust blocks most vigorously at 75–81°F, with acceptable growth between 68–86°F. For fruiting, most indoor growers target a slightly cooler range of 68–77°F, which encourages denser, thicker conks. Moving fully colonized blocks from a warmer incubation space to a cooler fruiting environment also helps signal the transition from vegetative to reproductive growth.