May 14
Shiitake Mushroom Logs
Shiitake mushrooms…..we would never have thought to grow them had we not attended a short course on small farm economics offered by the Extension Service. This was in 1985. We had just built our house and were hoping to find ways to support ourselves here on our place. So when we learned at this course that we could grow an exotic food using oak logs and our own labor it seemed a perfect fit.
The first year we tried this, under the guidance of the Extension agent, we prepared 500 logs. But shortly after the logs were cut and inoculated we were informed that the spawn obtained for us by the agent was sterile. So those logs became firewood, and we resolved to try again in 1987. Success rewarded our efforts with that crop of logs, and we have been growing shiitake ever since.
I cut logs from 3 to 5 feet long and from 3 to 10 inches in diameter…the greater the diameter the shorter I make the logs, so I can lift them with ease. We inoculate the logs with shiitake spawn, which we buy in bags that will treat 40 to 50 logs each. In the early days we would put up about 500 logs per year, but with advancing age we have cut back to between 250 and 300.
The process begins in January, when we start cutting firewood. Any branches or trunk segments that will make good shiitake logs are gathered up at the barn. Only wood from living oak trees—any species of oak—are used. Between January and the end of March the pile of logs slowly grows. We begin the inoculation process in early April. The only specialized tool used in preparing the logs comes into play during inoculation. It is a Hitachi mushroom log drill, designed to rev very fast so that the thousands of holes that must be drilled in all those logs can be drilled with speed. Twenty or so holes are drilled, about 6 inches apart, in the slender logs, and 30 to 40 holes are drilled in the larger ones. The drill has a stop that assures that the holes are about 1 inch deep. A regular shop drill with a 1/2 inch spade bit could also be used, but for any number of logs this will be a sloooow process.
We drill the logs on the sturdy wood table that we use to hold the tree baler during Christmas. I bring a log to the table, drill the necessary holes and then roll it forward. When the table has 20 to 30 logs on it, all drilled, Sally and I begin the actual inoculation. A chunk of the purchased spawn as big as the tip of a little finger is inserted in each hole and tamped down with a wooden dowel. We use melted wax (we melt down old candle stubs) to seal the filled holes. This prevents the spawn from drying out, which would kill it.
The inoculated logs are ‘cribbed up’ under the shade of pine trees. Cribbing begins by laying down two supports, to keep the bottom logs off the ground. Seven or 8 logs are laid on the supports, and then another layer is laid across the first layer at right angles. About 50 logs make up the crib. During this time in the crib, the mushroom mycelium works its way through the wood, priming the logs to sprout the next year’s shiitake harvest.
In May, 13 months after inoculation, the logs are taken from the cribs and are stood on end along wooden stanchions, alternating sides to form a long tepee-like array. We start production when the weather turns wet and humid, usually toward the end of May. To stimulate the logs to produce I immerse 15 or so at a time in a 6-foot long tank filled with water. After 24 hours or so in the water the logs are re-arrayed on the stanchions and covered with plastic sheeting to keep the moisture in. If all goes well, mushrooms will appear in 3 to 5 days. We pick them as they open up, refrigerate them until Saturday market, and sell them in Warrenton. After production the logs are given a rest of 6 to 8 weeks, and then they are ready to be soaked again. This process continues right up until early November, when the cold temperatures put a stop to production.
Shiitake logs usually produce strongly the first year, moderately the second, and poorly the third, although we have had some produce well for 4 years. And of course there are some that never produce at all. The mushrooms are really delicious and sell very well. They are a significant part of our farm economy and we hope to be producing them for years to come.
