Check your block upon arrival to make sure there are no tears or signs of mold from shipping. If the block has broken into pieces during shipping, gently press the block together and let sit 3-5 days undisturbed before moving to next step.
Lion's mane has notoriously thin and wispy mycelium, if the block appears uncolonized let it sit 2-4 days and it should begin to whiten.
Slice a 1-2" slit into the bag or a 1" "X" into the side of the block. Be careful not to cut into the block itself and just cut the plastic. If there are mushroom pins, consider creating the opening around a group of pins.
Fold down the top of the bag and deflate the block, tape the top down so that there is minimal room between the block and plastic except where the cut was made.
Place the Ready-to-Fruit block in the most humid part of your home (not in direct sunlight) or in a grow chamber or grow tent. The kitchen is a good household place in lieu of a dedicated fruiting chamber. Lion's Mane fruits best between 60-85°F.
Search online for easy to make fruiting chambers: monotubs, shot gun fruiting chambers (SGFCs) and tents with foggers/humidifiers are all great options and will likely increase success in fruiting and producing healthy fruits. Even a trash bag with plenty of holes can be used to increase humidity! If the Lion's Mane produced in a fruiting chamber have large stems and long thin teeth, more air exchange is needed.
2X daily (or more if your environment is dry) spritz the plastic with distilled/filtered water where the cut was made and look for mushroom "pins". These are the start of mushrooms! Pins should take ~1-2 weeks to develop from the time of opening the bag.
Continue to mist the fruits and plastic while they grow. Lion's Mane are usually ready to harvest ~7-14 days after pins form and should be harvested before the teeth elongate too much and produce spores for tastiest results.
Cut the mushroom cluster from the block and enjoy for your next meal!
Soak the block in fresh distilled/filtered water for 1-6 hours while inside the bag (pour into the opening) and then drain from the bag.
Put block back into fruiting conditions, you should get at least 1 more "flush" of mushrooms from the block. If pins do not form at the cut site, consider opening the plastic at the site of the largest set of pins for subsequent flushes and sealing the original site with tape.
