Wednesday, February 24, 2010

Woodland Mushroom Cultivation

Our previous attempts at inoculating logs and stumps with the mycelia of edible mushrooms have met with varied success. I thoroughly recommend Paul Stamets Mycelium Running: How Mushrooms Can Help Save the World. He suggests a multi-pronged attack on the wood: even the (vegetable oil based) lubricating oil for his chainsaw is inoculated with spores. From experience and from reading, I’ve also come to realise how important it is not to let the log or stump dry out.

Oyster mushrooms are saprophytic, that is they are decomposers. (The other basic categories are parasitic, mycorrhizal and endophytic). We’ve had most of our success with this one and decided to try again and use a different supplier to get another point of view.

Ann, of Ann Miller’s Speciality Mushrooms, supplies the inoculated dowels that we’re used to. (Mushroom spawn is also available in an amorphous mass of bran and sawdust but that requires a special tool to insert the plug into the hole in the log).

Included in her kits are flakes of wax with applicators; the wax seals the plug off from other airborne spores, to give our chosen mycelium the best opportunity to get established first.

She also suggested some variations on the technique we’ve been using to date. The stump gets covered with a black plastic bag, to help preserve humidity and then covered with brash to keep the sun off. When our chainsaw-wielding volunteers, Paul and Liam, thinned a patch of sycamores for next winter’s firewood, I asked them to leave the stumps standing to a comfortable working height of a couple of feet (60 cm). I also asked them to cut again, below their felling cut, to leave a flat surface in which to drill a ring of holes for the dowels and provide a cap to cover, and so keep moist, the inoculated face.

The two main problems I think we’ve had is using wood that was already infected with another mushroom (fortunately another edible mushroom!) and letting the stumps dry out. Ann says that watering stumps or logs with a watering can doesn’t wet the log, which need to be immersed in water for a while, impossible with a stump, meaning that we should spend more effort not letting them dry off in the first place.

Just two weeks later, I had a peer under the brash, under the plastic bag and under the wooden cap, to see that the mycelium is already running. We’ll keep and eye on them over the next few months and, if they look ready to flush, we’ll remove the plastic bags as it turns cooler and damper in autumn.

Permaculture-wise, we don’t need to do anything to kill the stumps, which would otherwise coppice and, after the initial effort and expense, we can leave the mycelia to work unassisted, eating the stumps and turning it back into soil, while intermittently throwing out edible mushrooms for up to five years.

photos show the dowels as they arrive from Ann; me applying wax; an inoculated stump; protected by a bag, the mycelium starting to run and one I prepared earlier, fruiting!