Harvest your mushrooms when they are fully grown. In about three weeks, you should see small mushrooms appearing. Continue to mist them with water and they should double in size each day. Keep their environment moist, cool, and dark to encourage their growth.
When the mushroom caps separate fully from their stems, they are ready to harvest. You can pluck the mushrooms out with your fingers, but this risks damaging the newly developing fungi beneath the surface. Instead, use a sharp knife to cut the mushrooms at the base of the stem.
It is best to rinse the mushrooms before cooking or eating. You can store harvested mushrooms in a paper bag in the refrigerator for up to a week