Grow guide

How to fruit a lion's mane grow kit

By Shroom Labs. Published October 30, 2026.

Cut one small X in a colonized kit, keep the air around it very damp, give it moderate fresh air and about 12 hours a day of low light, and keep it cool. Our lion's mane profile pins for 5 days at 18 °C (64 °F) and 94% humidity, then fruits for 12 days at 17 °C (63 °F) and 90%, under about 200 lux for 12 hours a day. That is about 17 days from opening to the end of the first harvest. Pick it while the spines are long and still white, before they turn yellow.

What a lion's mane kit needs to fruit

A lion's mane kit is a bag of hardwood substrate the mycelium has already grown through. To make it fruit you change four things: cooler air, very damp air at the cut, some fresh air, and a little light. Lion's mane is pickier than oyster on two of them. It wants the air damper, and it does better with less fresh air and less light than you might expect.

These are the settings in our free lion's mane grow profile. Pinning is when the first small knobs form. Fruiting is when they grow into a full head with hanging spines.

Setting	Colonization	Pinning	Fruiting
Days	16	5	12
Temperature	22 °C (72 °F)	18 °C (64 °F)	17 °C (63 °F)
Humidity	90%	94%	90%
Light	Dark	12 h a day, about 200 lux, blue	12 h a day, about 200 lux, blue
Chamber fan	15 s every 60 min	25 s every 20 min	25 s every 18 min

A kit arrives already colonized, so your count starts at pinning. Pinning plus fruiting is 17 days from cutting it open to the end of the first harvest. The whole profile, spawn to harvest, is 33 days.

Day by day steps for a lion's mane kit

Day 0, check the bag. It should be mostly white and firm. Our profile colonizes at 22 °C (72 °F) in the dark, so a kit that still looks patchy can sit closed somewhere warm and dark for a few more days.
Day 0, cut it open. Follow the instructions that came with the kit. If there are none, one small X on the side works. A 2025 lion's mane study cut a 3 by 3 cm X in each bag (Jozifek et al. 2025). Lion's mane grows from that opening, so one cut means one head.
Day 0, move it somewhere cool and dim. Aim for around 16 to 20 °C (61 to 68 °F), with room light or indirect daylight, out of direct sun and away from heater vents.
Days 1 to 5, keep the air very damp. This is the stage our profile runs wettest, at 94%. Mist the air around the cut and the inside of a loose tent a few times a day. Do not let water pool at the cut.
Days 1 to 5, give it light and a little air. About 12 hours of low light a day and some fresh air tell the block it has reached open air. Look for dense white knobs at the cut, not a fuzzy white layer.
Days 6 to 17, let the head grow. Keep the air damp, around 90%, and the room a degree cooler if you can, 17 °C (63 °F). Mist the air near the head, not the spines.
By day 17, harvest. Cut the whole head off at the base once the spines have grown out, and before the tips turn yellow.
After the harvest, rest and repeat. Clean up any bits left at the cut, let the block rest, then set it up the same way for a second flush.

Plug your open date into the grow timeline calculator to get calendar dates for each stage.

Why lion's mane wants high humidity

Dry air is the first thing to check with lion's mane. NCAT's ATTRA guide, a USDA funded grower program, aims for 85 to 95% humidity while fruiting and says lion's mane is especially sensitive to low humidity. When the air is too dry it forms small dense blobs instead of a full head with spines (NCAT ATTRA 2026). A review of lion's mane cultivation gives the same 85 to 95% range (Sokół et al. 2015), and the 2025 study grew it at 90 to 95% (Jozifek et al. 2025).

Wet is not the same as damp. NCAT links yellow or slimy spots and constant dripping to too much moisture or too little airflow. Mist the air, not the mushroom, and if water runs down the bag, ease off. A loose plastic tent with a few holes over the kit holds humidity between mistings in a dry room. Humidity and fresh air covers how the two trade off.

How much fresh air does a lion's mane kit need?

Some, but less than oyster. Our lion's mane profile runs the fan 25 seconds every 18 to 20 minutes while pinning and fruiting. Our oyster profiles run it 40 seconds every 10 minutes. The profile note is that too much air yellows the spines, and if the spines brown or yellow, cut fresh air and raise humidity a little.

Too little air causes a different problem. NCAT says that with low air exchange lion's mane turns fuzzy and misshapen (NCAT ATTRA 2026). The 2025 study vented its grow box to keep carbon dioxide under 800 ppm (Jozifek et al. 2025). A kit on an open counter usually gets enough. A kit in a closed cupboard or sealed bag does not.

Why lion's mane wants low light

Lion's mane needs light as a signal, not for energy, and it does not need much. The cultivation review gives 200 to 400 lux for fruiting (Sokół et al. 2015). Our profile runs about 200 lux for 12 hours a day and keeps colonization dark so the block does not pin early. Room light or a window with no direct sun is enough. Do mushrooms need light? has the numbers for other species.

More light is not better here, and that is where the pink comes in.

Why is my lion's mane turning pink?

Some lion's mane turns pink while it is young. The 2025 study from the Czech University of Life Sciences grew four strains. One stayed pure white in every trial. The other three showed pink in early development that got stronger with more selenium in the substrate and faded a bit as the heads matured (Jozifek et al. 2025). An earlier study also saw lion's mane go from white to white pink when selenium salts were added at 0.4 and 0.6 mM (Niedzielski et al. 2014).

A kit has no added selenium, so the part that matters at home is light. The 2025 study saw slight pink even in its plain controls, grown at 17 to 18 °C under about 500 lux for 24 hours a day. The authors point to the cool temperature, bright light and nonstop light as possible causes. When they dropped to 200 lux or lower on a 12 hour cycle, the heads came out white. They also call the pink a possible stress reaction and say it depends on the strain.

That is why our profile runs 12 hours at about 200 lux. If your kit is turning pink, shorten the light to 12 hours a day, move it away from bright light, and keep it in the 16 to 20 °C (61 to 68 °F) range NCAT gives for fruiting.

When to harvest lion's mane

Harvest while the head is firm and white and the spines have grown out. Our profile note is to harvest when the spines lengthen but before they yellow. The Minnesota DNR says lion's mane is best eaten white and that yellowing means aging and can taste bitter (Minnesota DNR). NCAT says the same: harvest lion's mane when the texture is firm and the shape is well developed (NCAT ATTRA 2026).

Cut it off at the base with a clean knife. Store it in the fridge at 34 to 38 °F (1 to 3 °C) in a paper bag or a vented container, not sealed plastic. NCAT gives most fresh mushrooms 5 to 7 days and says lion's mane can sometimes last a little longer (NCAT ATTRA 2026).

How to get a second flush

After the first harvest, clean off any bits left at the cut and let the block rest. NCAT suggests a rest of about 7 to 14 days between flushes, with the block kept damp (NCAT ATTRA 2026). Then set it up the same way. NCAT notes later flushes give diminishing returns, so expect a smaller second head.

If your lion's mane kit is not growing

Our profile expects knobs within the 5 day pinning stage. If there is nothing a week or so after that, it is usually one of these:

The air is too dry. Small dense blobs with no spines point here.
The room is too warm. Our profile fruits at 17 °C (63 °F), and NCAT puts lion's mane fruiting at 16 to 20 °C (60 to 68 °F).
It is sealed in a cupboard or bag with no fresh air. Fuzzy, misshapen growth points here.
It sits in the dark, or in bright light all day and night.
The cut dried out or was never made.

Mushroom grow kit not growing walks through each cause in order.

FAQ

How long does a lion's mane kit take to grow?

About 17 days from opening a colonized kit. Our profile gives 5 days of pinning and 12 days of fruiting before the end of the first harvest.

Should I mist my lion's mane kit?

Yes. Mist the air around the cut and inside a loose tent a few times a day, more in a dry room. Avoid soaking the spines or letting water pool at the cut.

Why is my lion's mane turning yellow?

It is aging, or the air around it is too dry or too drafty. Harvest it now. Next time pick sooner, and if the spines yellow early, cut back on fresh air and raise humidity a little.

Why is my lion's mane pink?

Usually stress, and it depends on the strain. A 2025 study got pink heads under nonstop 500 lux light at 17 to 18 °C and white heads at 200 lux or lower on a 12 hour cycle.

Does lion's mane need light to fruit?

A little. About 200 to 400 lux for 12 hours a day is enough. Room light or indirect daylight works.

Sources

Jozifek et al. 2025, Selenium Uptake by Hericium erinaceus Basidiocarps on Various Substrates and Their Effect on Growth and Yield, Agriculture 15(5):460
Niedzielski et al. 2014, Efficacy of supplementation of selected medicinal mushrooms with inorganic selenium salts, Journal of Environmental Science and Health, Part B 49
Sokół et al. 2015, Biology, cultivation, and medicinal functions of the mushroom Hericium erinaceum, Acta Mycologica 50(2):1069
NCAT ATTRA 2026, Mushroom Cultivation, USDA funded grower publication IP677
Minnesota DNR, Minnesota Profile: Lion's Mane, Minnesota Conservation Volunteer 2018
Our lion's mane grow profile, for every stage length, temperature, humidity, light and fan setting above, and our pearl oyster and blue oyster profiles for the oyster fan comparison