On Tuesday I toured the Mushroom Test Demonstration Facility at PSU. The tour was part of my Biology of Fungi class, and it was the second time I’ve been through the facility.
The process used to grow white button mushrooms at PSU involves six steps:
Step 1- Making the Substrate. The substrate for growing button mushrooms is a compost composed of horse manure, straw, switch grass, poultry manure, water, and gypsum.
Step 2 – Finishing the Substrate. The finishing process removes pathogens from the compost by elevating the temperature. Ammonia levels must also be reduced before mushroom production can begin. The substrate is put into trays.
Step 3 – Spawning. Spawning is the equivalent of seeding. Mycelium of the fungus that has been cultured on millet grains is put on the trays. The trays are then put in a growing room, where the temperature and carbon dioxide levels can be controlled.
Step 4 – Casing. After a couple of weeks the trays should have a considerable amount of mycelium on them. A layer of peat, mixed with more fungal mycelium, is added to the top of the trays.
Step 5 – Pinning. Careful control of moisture and carbon dioxide is needed to stimulate a good crop. The mushrooms begin to form in little structures called pins. These tiny white balls grow quickly into a harvestable mushroom.
Step 6 – Harvest. The mushrooms are harvested by hand. Typically each tray is harvested three different times. Following the third harvest the trays are emptied, and the substrate is discarded.
That was a relatively simple account of the mushroom production process. Each step involves various intricacies.
In Pennsylvania approximately 353 million pounds of button mushrooms are grown each year. That’s impressive. Think about how light a button mushroom is.
This morning I am headed out to the woods to hunt for mushrooms. No, I’m not planning a stir fry (as a general rule I don’t eat wild mushrooms). I need to collect a few specimens for my Biology of Fungi class.