I bought a package of King Oysters from Whole Foods (which was rather expensive) and I wanted to grow this mushroom for myself.
The stem butts were cut off the mushrooms so I decided to take slices of the inside tissue and add them to cardboard pieces inside of petri dishes. The cardboard I had put inside of a jar of water and boiled it in the microwave for 20 minutes. I took one layer of cardboard off of each piece and threw it away. I added the slices to the wavy side of the cardboard. I put the dished in the dark at 65 degrees Fahrenheit.
The pieces started to look a little fuzzy around day 5 and here is a photo from today, day 6. My goal is to spread the mycelium across the cardboard and then add it to a full jar of coffee grounds. Once the grounds are fully covered I'll add them to a bag of straw like I did with my grey oyster mushrooms. Growing mushrooms is so much fun. YOU MUST TRY IT! I'll keep updating this experiment here.