Environmental Conditions for Each Growth Stage

Growing Lion’s Mane can be surprisingly easy when your environment matches the growth stage. During incubation, the goal is steady warmth and patience while the block colonizes in a sealed microclimate. Pinning is the opposite: a cooler trigger, near-saturated humidity, fresh air, and gentle light to signal the mycelium to fruit. Then, as the mushroom develops, you fine-tune the balance with slightly warmer temps, high (but not dripping) humidity, and consistent airflow to keep the fruits dense, white, and full of long teeth rather than malformed blobs. Let's break down the ideal temperature, RH, CO₂/FAE, and light targets for each stage so you can reliably produce beautiful Lion’s Mane at home or on a small scale.

Incubation (Colonization Stage)

Maintain moderate temperatures, ideally 68–75°F (20–24°C). The mycelium grows fastest around 73-77°F (23–25°C), but temperatures within the normal room temperature range are also suitable. No special humidity control is needed while the substrate is sealed; the mycelium creates its own humid microclimate inside the bag.

Light is not required (colonize in dark or ambient light), as Lion’s Mane is fine growing in darkness during this vegetative phase.

Minimal fresh air exchange is required during incubation; in fact, CO₂ can accumulate in the sealed bag without harming mycelial growth (high CO₂ levels during colonization are even desirable to maintain the mycelium in a vegetative state). Target CO₂ in incubation can be several thousand ppm, so it’s not a concern until fruiting. 

Normal room conditions (dark shelf at ~70 °F (22 °C)) are sufficient for incubation.

Primordia Initiation (Pinning Stage)

Trigger pins by introducing a temperature drop. Aim for 50–60 °F (10–16 °C) for a couple of days if possible. High humidity, ~95–100% RH, is crucial at this early stage. Light should be introduced (at least ambient daylight or a 12-hour light cycle) to signal the mycelium that it’s at the surface.

Fresh air is essential: maintain low CO₂ levels (~500–800 ppm) by providing four or more air exchanges per hour. Many cultivators pin Lion’s Mane in humidity tents or small greenhouses. They might open the tent a few times a day or use computer fans set to timers to prevent the air inside from stagnating.

A cool-mist or ultrasonic humidifier can run frequently to keep near-saturation humidity. This balance of very moist but well-ventilated, cooler conditions will coax the mycelium to form thick, white primordia.

Fruiting (Development Stage)

Once the pins have formed (visible as white pom-poms, ~0.25-0.5 in (~0.5–1 cm), slightly adjust the maturation conditions.

Temperature: Allow it to rise slightly to 60–72 °F (16–22 °C). This warmer temperature speeds growth; however, avoid going above ~75°F (~24°C), as Lion’s Mane can become floppy and yield drops at higher temperatures.

Humidity: Maintain high humidity, but reduce pure saturation to 85–95% RH now. Too high (99–100% constantly) could encourage bacterial spots or overly wet mushrooms; too low (<80%) will dry the teeth and turn them yellow. You may notice that if the humidity dips, the outermost spines start to discolor. That’s a cue to raise humidity back up.

Fresh Air: Continue providing ample FAE. Lion’s Mane fruits will tolerate a bit more CO₂ than pins, but you should still target <1000 ppm CO₂.

In practical terms, this means no stagnant air. If you see fruits getting elongated “stems” or looking like a brain coral instead of a tight pom-pom, it’s a sign CO₂ is too high. Increase air exchange by fanning more often or running a fan, even if it means losing some humidity (you can always re-mist to compensate). 

A common beginner mistake is keeping fruits in an overly sealed tub or bag to prevent humidity, which can lead to malformed “blob” or “cauliflower” mushrooms due to CO₂ accumulation.

Light: Provide at least moderate light (e.g., a few hundred lux). Direct light is not needed; in fact, avoid direct sunlight, which can cause them to heat and dry. A fluorescent or LED lamp in the room, operated on a 12-hour cycle, is sufficient. Lion’s Mane doesn’t need as much light as some other mushrooms; think “forest understory” level lighting.

Harvest & Post-Harvest: Once mushrooms are harvested, no special environmental conditions apply until you attempt another flush (in which case, repeat the pinning parameters after a rest period).

If you opt for a second flush, consider submerging the block in cold water overnight (a form of cold shock and rehydration), followed by returning it to fruiting conditions, which may stimulate new growth.

By understanding and controlling these parameters, even a small indoor grow operation can achieve yields comparable to those of commercial setups.

Use a hygrometer/thermometer to monitor your grow space. Many growers maintain fruiting room conditions around ~65 °F (~18 °C) and 90% RH with constant gentle airflow to reliably produce high-quality Lion’s Mane.