We watched a two part video on YouTube about growing them in used coffee grounds. It said coffee shops will be glad to give you their used grounds, and sure enough all you have to do is ask. They even provided the bags for God's sake!
The video guy went through a lot of hoopla about getting mycelium to form on mushroom pieces on corrugated that he has supposedly pasteurized with hot water. Yeah!
This person was stressing keeping a sterile environment, while rubbing his hands on everything and flopping things around on a table. Yeah sure!
This I could not believe: At the end of the second video there is a notice printed on top of the frame that says the process got contaminated and did not work. Why the hell did he leave the whole video online? No wonder it got contaminated the way he was tossing stuff around.
Anyway, I have no idea of whether this is going to work, but I decided to give it a try using the sterilization methods used in plant tissue culture.
It would be nice if it did work, as mushrooms grow quickly, and once you have them going you can keep an endless supply coming along.