And can you prevent dangerous mushrooms from growing along side the good ones. How would you tell the difference?

Many of the Fungi Perfecti mushrooms suggested for outdoor culture, like Oyster, Morel, Shiitake, and Reishi, are quite distinctive. Also, you can start them out as a block you raise and harvest in your house, so you would become familiar with their appearance, then you inoculate the compost pile or sawdust bed with the spent broken-up block, so when the mushrooms grew you would know what they looked like. Anyway, I don't consider that a problem personally, I just want to get feedback from someone who has raised them. I am worried more about contamination in regards to decreasing yields.

Oyster mushrooms are the most disease resistant. There may be a problem with bugs in them when they are grown outdoors. They are easy to grow indoors though.

Lee AKA Fireraven9
If there is magic on the planet, it is contained in the water. -Â Â Loren Eisley