Delicious Decomposition

When we started Oak Shade Farm, our first act was to remove some of the surplus oak-shade. Irony notwithstanding, it is very difficult to garden or grow evergreens in thick, deciduous shade, and nearly all of our 23 acres was wooded when we bought it in 1980. Most of the trees were from 50 to 80 years old, and many had to go if we were to farm successfully. This raised the question: what do we do with so much wood?

The answer: heat our home and grow shiitake mushrooms on the rest. Most of the trees were oak of various species, the preferred tree of the shiitake wood-rot fungus. So, as we created our clearings we cut up the pines, poplars and maples for firewood, and we cut the oak up to produce mushroom logs.

Wood selection is to cultivating shiitake as soil selection is to cultivating vegetables. We try to cull oak from crowded areas, selecting live trees for shiitake growing and dead ones for firewood. The live trees have more sugar-containing sapwood than dead or dying trees. We cut the logs into lengths of 3’ to 5’, depending on their diameter, and we use diameters ranging from 2″ to 8″. We cut and stack the logs after Christmas, and inoculate in April.*

A stack of logs that will produce mushrooms in 2014 awaits inoculation.

Log Inoculation

Inoculation begins with drilling from 20 to 40 holes in each log: more holes for big logs, less for the thinner ones. The drill bit we use makes a hole 1″ deep, and the drill is specially made for drilling Shiitake logs. It goes very fast, so creating the holes in a log takes only 30 seconds or so. Once the holes are made we use a plunger to insert the spawn into the holes, then we dab melted wax on each hole to seal in the spawn.

The plunger and a pot of shiitake infused sawdust.

Shiitake infused sawdust

Wax holds the shiitake spawn in place and helps prevent contaminating the interior of the log with other fungus spores.

Wax helds the shiitake spawn

The inoculated logs are cross-stacked in the shade, where they will experience natural temperature and moisture fluctuations, but never prolonged, direct sunlight. The mushroom mycelium gradually moves from the plugs along the wood until it permeates the log all the way to the end-grain. A few logs will volunteer mushrooms in the Fall, but most will not be ready to produce until April or May of the year following inoculation.

This method of stacking allows the logs to ventilate, dissipating mold-causing moisture that can be trapped in the center after long wet periods.

Inoculated logs

Most logs will produce mushrooms well for 2 years and some will yield for a third year. Some logs never yield any–many variables determine shiitake production, but wood selection and moisture content are the most important and are very difficult to get right 100% of the time. We sell the mushrooms at our farmers’ markets, and almost always sell out. Shiitake are a delicious and profitable way to make use of a plentiful Virginia resource.

Thanks to everyone who came out to our Shiitake Day on the farm! We had a lot of fun and we hope you did too.

Shiitake mushrooms

*It is usually recommended that you introduce the inoculum within a couple weeks of the tree dying. Our schedule makes this rather difficult, and we have had success with our way of pacing the process.