If you undertake growing some mushrooms from spawn, here is a great way to soak your straw bales.
There are several varieties of mushrooms that can be grown in straw beds including the delicious winecap stopharia (Stopharia rugosoannulata). Other varieties of fungi can be grown by placing plugs of the spawn directly into logs. Spawn can be purchased from companies like Field and Forest in Pestigo, WI.