There are ways of growing Mushrooms outdoors but they are very unpredictable and are more of a challenge than anything else. They involve an awful lot of stable manure - enough to make a pile 6' x 6' x 6', turning it regularly, measuring the temperature to ensure it is a constant 140F to 'cook' the compost and then getting it to remain at a constant 65F to grow the mushrooms. It has to be impregnated with the Mushroom spawn and a capping put on it. After all this 'IF' you are lucky you may get some Mushrooms.
The easiest way to grow them is by buying one of the commercial mushroom kits that are now available. They consist of a box, usually polystyrene or waxed cardboard, some stable manure and a bag of special compost or 'capping'. This capping usually contains the Mushroom spawn. It is just a simple matter of spreading the capping on top of the manure, watering, and keeping in a warm place and waiting for the crop of Mushrooms.
Ensure that when you buy the kit it is fairly new and has not been in the shop for some considerable time and that you use it as soon as possible. The mushrooms are normally ready for picking about 3 weeks after sowing and will crop in flushes over an 8 - 10 week period.
© copyright 1999, P. A. Owen