Lion's mane Fruiting blocks!

You can purchase one from us here!


Blue Sky Fungi Lion's Mane fruiting blocks are made of fully colonized hardwood sawdust and small wood chips that are supplemented with wheat bran and gypsum.

Special Note: Do not open your mushroom fruiting block until you have read through ALL these instructions and prepared all the necessary materials. The Lion’s Mane mycelium (the fungi that forms the mushroom) will be the thin white growth that is growing on the sawdust block. Before you begin, make sure that the mycelium block was not cracked or broken apart within the bag. If the block is cracked, place the sealed bag in a dark place and don’t move it around. Allow the mycelium to recover and regrow for a few days undisturbed. If it starts growing a thick, white, blob-like mass near the filter patch on the bag, it is ready.

ALWAYS!!! use non-chlorinated water to keep the mycelium moist. Well water is good, but if your tap water is chlorinated, you can use filtered water or leave an open container of water out overnight to dissipate out the chlorine naturally

Placement Indoors: Find a place inside that is of average room temperature, has indirect lighting (enough to read words on a page, but not in direct sunlight), and away from drafty air currents, fans,  heat sources, and materials that are porous like wood surfaces or carpets (spores drop from the mushroom). A more humid place like a basement is better than a really dry place. You will place a humidity tent (a plastic bag with air holes cut out of it) over and around the block to maintain a high humidity environment. We recommend you place the block on a plate or pan to catch the water that drips off the side of the humidity tent.

Use of a Humidity Tent: Sometimes a location will require the use of a humidity tent, which is basically an oversized plastic bag with many holes. The idea is to make an environment that holds humidity/moisture and will allow fresh air to enter (and CO2 to exit). You do not want the humidity tent to be touching the mushroom, but rather creating an environment around the mushroom. The humidity in the tent can be maintained with a spray bottle. Lift up the tent/bag and spray the fruiting block and the inside of the plastic bag so it appears moist and water droplets are visible, or you can just spray through the holes in the plastic bag.

Do this 2 to 3 times a day (or more if warm, dry conditions exist). Place a pie-pan or broiler pan under the fruiting block to collect the water.

Lion's Mane (hericium erinaceus)


Temperature: 50 to 80 degrees F        Humidity:  80 to 100 %

The Lion's Mane mycelium will be the thin white growth that is growing on the sawdust block. If it starts growing a thick, white, blob-like mass near the filter patch on the bag, it is ready.

The block can be initiated without mushrooms forming.

Setting Up and Initiating Fruiting: Prepare the space you would like your Lion’s Mane to grow in. The block will remain in the plastic bag during mushroom growth, but will grow out of a small, X-shaped slice in the side of the bag or out from where the white filter patch on the bag is. To determine where to make the opening, look for a thick, white, blob-like mass growing on the surface of the sawdust, this is the primordia of the Lion’s Mane mushroom. If you see that mass on the top near the filter patch, cut the entire patch off with scissors or a razor blade; you may need to cut away more plastic to expose some of the mycelium block to fresh air. If no large mass is forming, or you want to fruit the mushroom out of the side, cut a 2 cm long X-shaped hole in the side of the plastic bag. Lion’s Mane mushrooms will grow out of the hole toward the fresh air and when maturing, the teeth form down with gravity.

When everything is set up, follow these steps:

  • Clean your hands and the scissors or razor blade.

  • Determine the site where you want the mushroom to grow and cut the plastic.

  • Gently squeeze the excess air out of the bag and fold the top portion over. You can tape down the bag flap to keep it tight against the block, or you can turn the bag on its side to pinch down the plastic flap. You may want to prop up the bag above the counter top to allow the teeth to cascade down and out of the mushroom.

  • Place the humidity tent (plastic bag) over and around the entire mushroom block and the plate and/or support object under the block. You should spray the inside of the bag with a water mist from a spray bottle prior to covering the block with the humidity tent.

Daily Care: Now that your mushroom fruiting block is set up, you need to perform some daily care.

  • Maintain a high humidity environment within the humidity tent. There should be visible droplets of water on the inside of the humidity tent. Do this with the spray bottle several times per day.

  • Allow for good airflow. There should be enough holes in the humidity tent to allow fresh air exchange and maintain the humidity for several hours. The humidity tent can also be removed and replaced to promote air exchange.

  • It is recommended to carefully remove the bag each time you spray the inside of the bag with the spray bottle, then carefully replace the humidity tent to create an open pocket around the growing mushroom. Try to avoid allowing the plastic humidity tent to touch the growing mushroom. (Remember to use non-chlorinated water or breathe off the chlorine first)

Growing: Lion’s Mane mushrooms should start to grow within 2 weeks after opening the bag and take about 1 to 2 weeks to grow. Continue to water the humidity tent while it has mushrooms growing but try to avoid getting a lot of water onto the mushroom itself. The blob-like primordia will get larger and will eventually form teeth-like structures that will grow like a waterfall or a lion’s mane!

Harvesting: The mushroom is ready to harvest a few days after the teeth form. The teeth will quickly grow longer and are dropping spores at that point. The quality of the mushroom will begin to degrade after the teeth are about 2 cm long. You can harvest the mushroom by either cutting it off from the surface of the block, or if it grew out of the X-shaped hole in the side, simply hold and twist off the mushroom. Younger mushrooms are denser and will have a better shelf-life than an old, long-in-the-tooth mushroom. And you can stop watering the bag a day before you harvest to let the mushroom dry out a bit.


Don’t get rid of the block. Lion’s Mane will produce several flushes of mushrooms, but you will need maintain the humidity in the tent to promote adequate growing conditions.

You can expect at least 2 flushes of mushrooms from these blocks. The next mushroom will most likely form at the same site as the first, but you can also make a new hole for it to grow out of. If no more mushrooms form, or you cannot provide adequate daily care, then you can try to place the block outside to grow in the spring or fall weather. Just make sure to keep it in a humid environment and out of direct sunlight. If to no avail, then the block will make excellent mulch or compost for your garden.

For a PDF copy of the Lion's Mane Fruiting Block Instructions, click here.

frequently asked questions

Mycelium require certain conditions to produce a mushroom. These conditions include specific temperature, humidity levels, CO2, and light. Many problems encountered with growing mushrooms are a result of an imbalance of these conditions. The solution is to manipulate the environment to be favorable for the mushroom to produce and survive. The following section will answer some frequently asked questions about growing Shiitake mushrooms from a Blue Sky Fungi fruiting block.

The block is not producing mushrooms and feels light and dry.

This is most likely a problem of humidity and available water. You should be hydrating the block at least once a day, but if your growing environment is too dry, you may need to hydrate it more than that. Always use a humidity tent for Lion's Mane. Remember to always use non-chlorinated water!

I am hydrating the block daily but the mushrooms still won't grow.

This is might be a problem of temperature. Make sure it is not too cold or too hot where the block is placed. Also make sure that the block is not placed in direct sunlight.

The top growth is thick and hard to determine the mushroom primordia location.

If the block is not opened within a month of the date on the bag, the mycelium on the top may become thick and dry. The top mycelium growth may need to be scraped off to the sawdust layer to initiate a new mushroom primordia formation. Squeeze the air out of the bag and leave a portion of that scraped off section exposed to the fresh air. The mushroom should grow out of that scrape scar.

The mushroom is not growing in a round shape. It has a lot of spiky arms.

This is most likely a problem of CO2. Mushrooms are like us: they breathe oxygen and exhale carbon dioxide. The long spiky arms are a direct response of too much CO2. Put more air holes in the humidity tent, or remove and replace the humidity tent for fresh air exchange.

It looks like bacteria or mold is growing on the surface of the block.

Competitor organisms are everywhere and opportunistic. It is not uncommon that small blotches of bacteria or mold will grow on the surface. Bacteria and molds are generally shades of green, yellow, blue, spotty white, and black. Lion's Mane will look white. Use hydrogen peroxide or very dilute bleach dabbed gently on the infected areas. You can scrape off infected spots with a paper towel after treating them with peroxide. If the surface contamination cannot be overcome, it may be time to retire the block to the outdoors. You can set it outside in a shady spot and allow it to get wet. The outdoor conditions may be favorable for mushrooms to continue to grow.

Is it safe to eat the mushrooms if mold is growing on the block?

Short answer is: yes, if you are cooking the mushrooms. This is one of the many reasons why it is important to cook all mushrooms. Most of the time the infection is growing on the skin of the block and is benign to the mushroom. If the mold or bacteria has spread to the mushrooms, then probably not, but mushrooms in the wild generally will host a community of organisms. If you are in doubt, compost the mushrooms, clean the block, then try again.

What if the block breaks or the corners on the bottom break off when it is removed from the plastic bag?

This is no big deal as the mycelium will heal itself back together. So if the corners break off when the bag is opened or folded, it is not a big deal. However, if a significant crack in the block has resulted from transport or an accidental drop, allow the block a few days to recover and heal itself within the bag prior to opening.

What if I go away for a few days or weeks while I'm growing the mushrooms?

Harvest the mushrooms before you leave and let the block stay in a humid environment. This may have to be outside if the temperatures are not too cold or too hot. It is not advised to bring the block back inside for growing, as it may be a new home for bugs. And you don't want those could be your new house bugs.


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