The parasol mushroom (Macrolepiota procera) is native to my land so I have figured out it will be easy to establish a patch of these in my garden. I have prepared a bed with layers of wet corrugated cardboard, and I have used both spore prints and stem butts with some mycelium between the layers. I have covered this with a layer of wood chips and some cloth on top. I have moistened it when there was a dry spell, so I'm pretty sure it has never dried out. It was never too wet as well, since my soil is very sandy and has a very good drainage. After half a year I do not see any sign of mycelium in this bad. What I'm doing wrong?