Growing shiitake mushrooms on logs is one of the most satisfying and sustainable means of cultivating mushrooms. It’s more cost-effective than buying from a grocery store, and it’s a fun project to do with friends or family!
Sourcing Wood:
Healthy, living trees can be felled for mushroom bolts nearly any time of year, though to maximize yield and longevity you can time harvest with sap flow. Traditionally, log cutting and inoculation happen in late winter and early spring before bud swell. Fall provides another excellent window, after ⅓ of a tree’s leaves have turned color through leaf drop. At these two times, nutrients will be concentrated in the wood and bark should be tight, making them ideal for inoculation.
In the spring, between budding and full leaf out, nutrients in the wood are used for pushing out flowers and foliage and bark can be loose. So yields can be more variable and logs with damaged bark are at risk of contamination. Intact bark is important for the spawn run.
Sourcing Wood:
Healthy, living trees can be felled for mushroom bolts nearly any time of year, though to maximize yield and longevity you can time harvest with sap flow. Traditionally, log cutting and inoculation happen in late winter and early spring before bud swell. Fall provides another excellent window, after ⅓ of a tree’s leaves have turned color through leaf drop. At these two times, nutrients will be concentrated in the wood and bark should be tight, making them ideal for inoculation.
In the spring, between budding and full leaf out, nutrients in the wood are used for pushing out flowers and foliage and bark can be loose. So yields can be more variable and logs with damaged bark are at risk of contamination. Intact bark is important for the spawn run.
Any size logs will work. You can use branches or saplings if that is what you have available. Small-diameter wood will colonize faster, but will not produce for as many seasons as a larger log. You don't want the logs to be so large or heavy that they are difficult to use. For drilling methods, a 4-6'' diameter with a 3-4' length is ideal. For the totem method, they can be up to a foot (or more!) in diameter and 12-18'' high.
Source logs from a sustainable forester or use sustainable practices in culling trees for mushroom production. For more information on selecting tree species for mushroom growing, follow this link.
Inoculation:
Logs should be inoculated within a few weeks of cutting. This allows the cells in the tree to die but is not long enough for the log to dry out or for other competitor fungi to become established.
The process for log inoculation is relatively simple: drill holes in a freshly cut hardwood log, fill the holes with sawdust or plug spawn and seal the holes with melted wax. You can optionally seal the ends of the log as well. Then, the logs should live outdoors someplace shady, incubating until they’re ready to fruit.
The wonderful thing about mushroom logs is that you will get multiple years worth of gourmet mushrooms without having to re-inoculate your logs. On average a mushroom log will produce for 1 year per inch of diameter of the log. So, if you inoculated a 5-inch diameter oak log with shiitake sawdust spawn, it will most likely produce for 5 years!
Inoculation:
Logs should be inoculated within a few weeks of cutting. This allows the cells in the tree to die but is not long enough for the log to dry out or for other competitor fungi to become established.
The process for log inoculation is relatively simple: drill holes in a freshly cut hardwood log, fill the holes with sawdust or plug spawn and seal the holes with melted wax. You can optionally seal the ends of the log as well. Then, the logs should live outdoors someplace shady, incubating until they’re ready to fruit.
The wonderful thing about mushroom logs is that you will get multiple years worth of gourmet mushrooms without having to re-inoculate your logs. On average a mushroom log will produce for 1 year per inch of diameter of the log. So, if you inoculated a 5-inch diameter oak log with shiitake spawn, it will most likely produce for 5 years!
Mushroom log yields depend on the type of wood chosen, the species you are inoculating, and environmental conditions. Generally speaking, dense hardwoods take longer to fully colonize but will continue to fruit for more years, while soft hardwoods (like poplar) will fruit sooner for fewer years. And wood with more sapwood than heartwood may yield more mushrooms.
For fall inoculation in grow zones 8 and higher, we recommend protecting logs from freezing temperatures. Logs can be overwintered in heated spaces, tucked away close to the walls of heated structures, or stored close to the ground and covered with leaves, blankets, and tarps.
Check out the video above if you'd like to learn more about choosing a mushroom log and using shiitake sawdust spawn with our trio of log inoculation tools: our specialized 12mm mushroom drill bit, our inoculation tool, and our angle grinder adapter.
For smaller projects, we recommend shiitake plug spawn. If you’re just getting started, you may want to consider a Shiitake Mushroom Log Growing Kit. They come with everything necessary for inoculating 1-2 mushroom logs. There’s more information about them in the video below!
History of Cultivation:
Mushroom log growing, specifically of shiitake, is hundreds of years old.
The earliest accounts of Chinese cultivation of shiitake in what is now Southern Japan, date back to the 1200s. First prototypes of farming involved dragging fallen boughs of a native evergreen tree related to oaks and beech trees, called a shii, that had been found with sprouting shiitake mushrooms into the courtyards of enterprising individuals.
The etymology of the word shiitake is a mixture of the word shii, a type of tree, and a Japanese word for mushroom, take.
History of Cultivation:
Mushroom log growing, specifically of shiitake, is hundreds of years old.
The earliest accounts of Chinese cultivation of shiitake in what is now Southern Japan, date back to the 1200s. First prototypes of farming involved dragging fallen boughs of a native evergreen tree related to oaks and beech trees, called a shii, that had been found with sprouting shiitake mushrooms into the courtyards of enterprising individuals.
The etymology of the word shiitake is a mixture of the word shii, a type of tree, and a Japanese word for mushroom, take.
The tree boughs would continue to produce the edible shiitake mushrooms over subsequent years. Over time the method evolved. Early shiitake farmers would take freshly cut shii logs, purposefully damage the bark, and place them beside their wild forest collected shiitake logs. As the wild fruiting mushrooms dropped spores onto the logs beneath, they would sometimes begin to colonize the fresh wood and produce cultivated shiitake mushrooms.
Shiitake cultivation took a giant leap forward in the 1940s when a student at Kyoto University named Kisaku Mori produced the first batch of shiitake mushroom spawn by growing mycelium onto wood chips. When they were adequately colonized he injected the myceliated wood chips it into holes or notches in oak logs. The Mori Method moved away from working with spores to inserting already growing mycelium into fresh logs. This technological leap vastly improved the effectiveness of mushroom log cultivation and birthed a multi-billion dollar industry in Japan over the decades following.
Happy inoculating!