Mushroom Logs

Mushroom logs are lengths of freshly cut hardwood deliberately infected with an edible fungus, which feeds on the wood and pushes mushrooms out through the bark. The fungus is introduced as spawn - itself grown on grain or sawdust - tapped into drilled holes that are then sealed with wax to keep competing moulds out. The stack is left alone after that, making food from deeply shaded ground under canopy or against a shaded wall where no other food crop would grow.

Shade and moisture decide whether a stack works. A log that dries out stops producing, so the logs sit off the ground in even shade, sheltered from sun and wind. They are cut about 8 to 20 cm (3 to 8 in) across and 90 to 100 cm (36 to 40 in) long, and rested roughly two weeks before the spawn goes in. Speed matters more than the species: one field trial found no clearly better hardwood, but logs inoculated early in spring yielded significantly more than later ones, so the advice is to inoculate soon after felling. Nothing is picked for at least a year, production builds through the second and third, and the logs are usually spent by about five.

Mushrooms can also be brought on by forcing, which means submerging a whole log in cold water for about a day and never beyond two, so the site needs a trough a log will fit in. Mushrooms appear three days later and are ready around twelve. Forcing is where the practice is most often ruined: a log needs eight weeks between soakings, and pushing past that exhausts it rather than increasing the take. Logs are labelled with their inoculation date, since the schedule runs from it. A stack pairs with managed woodland that supplies both bolts and shade. Yields are modest and vary widely from log to log. The commonest failure is not biological - the work comes in heavy bursts with little in between, and in one trial of twenty-seven growers, seven never harvested at all.