Abstract: A mushroom growing method and apparatus in which a tray is filled with compost mixed with mushroom spawn, and the compost is covered with a layer of casing medium. The tray is supported horizontally while the mycelium colonizes the casing medium, and is then supported in an upright disposition under mushroom growing conditions so that the mushrooms grow from the upright face of the consolidated casing medium. Two trays may be supported back-to-back in an upright disposition against a stanchion. Alternatively, the trays may be hinged together and lifted to rest against each other back-to-back. The casing medium layer is watered by wicks dipping into water containers.