Growing Mushrooms on Wood
Growing mushrooms on a log at home is an excellent project for those interested in mycology (the study of fungi) and for anyone wanting to enjoy fresh mushrooms. The process might require some patience as it takes months for the mushrooms to fruit, but the experience can be rewarding and educational.
- Hardwood logs (Oak, maple, or beech are commonly used)
- Mushroom spawn plugs (Shiitake, maitake, or oyster mushrooms are good options)
- Drill with a bit slightly larger than your mushroom spawn plugs
- Wax (Cheese wax, beeswax, or soy wax work well)
- Small brush
- A hammer
- A saw
- A clean working space
Choosing and Preparing the Logs
The first step is selecting an appropriate log. As a rule, hardwoods are the best choice for cultivating most types of mushrooms. Oak, maple, or beech are commonly used due to their dense cell structure, but many other hardwoods will work as well. Avoid using softwoods or aromatic hardwoods such as cedar or eucalyptus, which have natural anti-fungal properties. The logs should be 3-6 feet in length and 4-8 inches in diameter for manageable handling and optimum growing conditions.
Cut the logs from live trees during late winter or early spring when the sap is running and the bark is easy to keep intact. This ensures the logs are filled with nutrients that mushrooms need to grow. Leave the logs to sit for about two weeks to let the natural antifungal agents in the tree dissipate but not much longer than that, as other fungi and pests might colonize the logs.
Using your drill and bit, make holes about 1 inch deep in the log. The holes should be spaced approximately 6 inches apart in a diamond pattern along the log to provide plenty of space for the mycelium to grow. Ensure the holes are drilled in rows about 2-3 inches apart from each other. This drilling pattern will ensure wide mycelial spread throughout the log.
Inoculating with Mushroom Spawn
Now, you'll introduce the mushroom spawn into the log. The mushroom spawn plugs are essentially dowels that have been inoculated with the mycelium of the mushroom you wish to grow. Take a plug, insert it into a hole, and use the hammer to tap it in gently until it's flush with the bark of the log.
Sealing the Plugs
After all the holes are filled with the plugs, melt the wax. Using the small brush, apply the hot wax over the plugs and the ends of the log. This step seals the holes and protects the spawn from drying out and from potential competitors, such as insects or other fungi. It also helps keep the moisture in.
After inoculating and sealing the logs, they need to be placed in a shady, moist location to allow the mycelium to colonize the log. This is called the incubation period. The logs should be kept off the ground to prevent other fungi from colonizing them. You can stack them in a crib stack or lean them against a fence or wall. During dry periods, water the logs with non-chlorinated water to prevent them from drying out.
This incubation period can last anywhere from 6 to 12 months, depending on the mushroom species and the size and type of the log. During this time, the mycelium is growing throughout the log, consuming the lignin and cellulose in the wood.
Once the mycelium has fully colonized the log (you can often see white mycelium in the ends of the logs or under the bark), it's ready to produce mushrooms, or "fruit". Sometimes, this happens naturally with seasonal changes in temperature and moisture. Other times, you can stimulate fruiting by soaking the logs in cold non-chlorinated water for 24 hours. This process, known as "shocking," mimics the natural conditions that signal to the mushrooms that it's time to fruit.
After the log has been shocked, place it in a humid, shady location. Within a week or two, you should see tiny mushrooms beginning to form. These will grow quickly, and within just a few days, they'll be ready to harvest.
Harvesting and Reusing the Logs
You can harvest the mushrooms when the caps have fully opened but before they begin to turn upwards. To harvest, twist and pull the mushroom off the log or cut it off at the base with a knife.
After the log has produced a flush of mushrooms, it needs to rest and regenerate its energy for about 6-8 weeks before it can produce another flush. During this rest period, keep the log in the shady, moist location where it was during the incubation period. The log can continue to produce mushrooms for several years until all the nutrients in the log have been consumed.
Growing mushrooms on logs at home is a rewarding and sustainable method of cultivation. Plus, the satisfaction of harvesting and eating your homegrown mushrooms is hard to beat!