Button or field mushrooms can be seen growing in paddocks at the right time of year. To replicate growing them at home I first made a heaving heap of compost out of bales of straw, horse manure, gypsum and water. It was turned every few days to make sure it was well composted.
After several weeks the compost is ready to use. Handfuls are mixed with the mushroom spawn in tubs and placed in the growing room.
A week later a special mix of peat and other ingredients is spread over the top of the tubs (casing) and they are put back into the growing room.
The tubs are monitored and misted as the tiny mushrooms start growing over a week or so until they are ready to be picked. The longer they’re left the bigger they’ll get.