The making of a mushroom crop

Step 1: Fung Yang, owner of Small Kine Farm, starts the two-month mushroom production process by mixing tree trimmings with animal manure to make compost. Heat is required to decompose the mix, but rather than use an external heat source, he traps heat generated biologically from microorganisms in the compost. The mix is kept 12 to 14 days in a shipping container, where the temperature is kept between 165 and 185 degrees.

Step 2: The compost is moved to an airtight container, where internal heat generated from microbial activity pasteurizes it. The process runs 10 to 12 hours at 135 degrees.

Step 3: The clean, pasteurized compost is called substrate, an organic material that is inoculated with mycelium, which allows mushrooms to propagate. The substrate is kept in yet another sealed container to protect it from bacteria and insects. After 10 days at 75 degrees, the mycelium has colonized the substrate.

Step 4: Colonized substrate is covered with a “casing soil” of peat moss and pulverized limestone, which mimics layers of leaves that fall to the ground in nature. The mycelium grows up and into the casing soil (it would grow into decomposed leaves in a natural environment).

Step 5: After two weeks Yang shocks the mycelium with fresh air, oxygen and a drop in temperature to encourage reproduction.

Step 6: In 10 days tiny mushrooms have sprouted, and in five to seven days they’ve developed into crimini mushrooms. A couple days later they are full-size portobellos.

Aftermath: Several cycles of mushrooms can be harvested from one substrate, every five to seven days. After 20 to 30 days the substrate is depleted of nutrients but is perfect for fertilizing plants. “We have a full-loop production cycle, meaning we are a zero-waste farm,” Yang said.