One really cool thing that I learned how to do while working at Burkett Farm was mushroom log inoculation. I spent a lot of time on this task during the coldest weeks of winter, when there was hardly anything else to do except mulching.
It’s important to start with freshly cut logs which have not yet begun to decompose, so that you can give your mushrooms a head start to establish themselves before competitive wild fungi have a chance to colonize the logs. I think one of the reasons that mushroom log inoculation is done in the wintertime is that logs that have just been cut during this time will have sap more saturated with sugars, which helps the fungi grow.
It’s also important to use logs from the trees that your mushrooms prefer. Different types of mushrooms, such as Pearl Oyster mushrooms versus Phoenix Oyster mushrooms, “prefer” different types of wood, such as maple versus spruce. For example, oak wood is considered the best wood for growing Shiitake mushrooms. Additionally, the wood you use will impact the overall yield, as well as the duration of mushroom production. And if the wood comes from a tree grown in fertile soil, the nutrient content of the wood will, of course, be better.
In addition to the logs, you will need a battery-powered hand drill, a drill bit, duct tape, mushroom spawn plugs, a mallet, wax (unscented wax candles will do in a pinch), a brush or other tool for spreading melted wax, a bucket, and a small propane burner.
First, turn on the propane burner and heat up the wax (or candles) in a bucket over the burner. While the wax is melting, use the drill to make holes for the spawn plugs. The drill bit should equal the plugs in length (usually, the product description for the plugs will specify the drill bit size needed) but if it’s too long, you can wrap duct tape around the drill bit’s base to guard against drilling too deep. Drill holes about 6 inches apart, in rows about 2 inches apart. Then, use the mallet to pound the spawn plugs into the holes, until they are flush with the outer surface of the log.
Once the plugs have been hammered into the log, use the brush to paint the melted wax over each plug to create a seal. This seal should help prevent drying and contamination. Repeat these steps with each log, and then stack the logs in a hashtag formation in a shaded area.
Spawn plugs are composed of a substrate, such as sawdust, which has been inoculated with mycelium, because growing mushrooms from already existing mycelium is more reliable than growing mushrooms from spores. The fungal mycelium will colonize the logs, and grow and expand within the wood. In time, the fleshy fruiting bodies of the mushrooms (the edible pieces) will emerge from the logs.
Since I like eating mushrooms, and I’m always curious about where my food comes from and how things are produced, learning about how edible mushrooms are grown, and participating in that process firsthand, was a really fun, intriguing experience.