Ben’s permaculture professor at NC State, Will Hooker, has been kind enough to allow me to tag along on some of their field trips and workshops. Yesterday the class was invited to his home in Raleigh (just down the bike path from where we live) to learn about mushroom logs and how to make one.
We started with 3′ wide, 4-6″ diameter hardwood logs and 1″ long dowel plugs that are pre-colonized by shiitake mycelium. The logs we used were sweetgum and oak, but you can use any hardwood for shiitake as long as the bark is thick and tough. It is important to use logs that are only 4-6 weeks old (from the time the tree was cut down). If you use logs right away, the natural defenses in the wood will kill the shiitake mycelium. If you wait too long (past 6 weeks), other undesirable fungi can colonize the log first.
To begin, take each log and drill 1.5″ holes with a 5/16″ drill bit about 6″ apart in a row along the length of the log. Continue drilling the rows of holes in a “diamond” pattern, covering the entire log. Then, take the dowel plugs and hammer them into the holes, making sure they’re flush with the bark.
After all the dowel plugs are hammered in, paint over the plugs, each end of the log, and any blemishes in the bark with melted beeswax to create a protective seal. Stack the logs in a shady area and keep them moist by watering them once per week.
Plugging the logs with the dowels and keeping them moist encourages the mycelium to colonize the entire log. Once the colonization is complete (about one year), mushrooms can be “forced” to produce by soaking the logs in water for 24-48 hours. After the soak, stand the logs up against some kind of support so the mushrooms have room to grow. Will mentioned an alternate method which is to beat the crap out of them with a mallet (but don’t break the wood); this simulates the effect of the tree falling in the forest.
The best time of year to make the logs is a few weeks before consistent overnight frosts, so the mycelium have enough time to start growing before the winter months. You can yield a few harvests (called “flushes”) of mushrooms off each log during the spring and summer.
A mushroom is ready to be harvested when the outside of the cap is still slightly pulled in, like an umbrella. (Ones with the edges starting to fan out are still edible, however.) It is recommended that you cut them off instead of pulling them out so that the plug stays in place.
In a little nook in his back yard, Will had several logs with shiitakes that were ready to harvest. He cut them off and cooked them for us to taste and they were just about the best mushrooms Ben and I have ever eaten. :)
These sites have more detailed information about making mushroom logs:
Natural Log Shiitake Mushroom Production and Processing
How to Care for and Fruit Your Shiitake Mushroom Log
Order Mushroom Plugs at Fungi Perfecti
