Dormancy: When it is, What it is, and Why it is Important for Mushroom Cultivation

Fall is a great time to think about starting or expanding your shiitake log family. Trees have fallen into dormancy, but leaves are still on the trees which can help with tree identification, ensuring you choose the best tree species for the mushroom you plan on growing.

Timing of cut chart
Autumn scene with canopy color change
Fresh cut logs for mushroom cultivation

Autumn Wood Harvest for Shiitake Logs

Fall is also a good time to view a tree stand critically to visualize which trees need to be removed because they are suppressed by or are suppressing their neighbors. These trees can be harvested this fall and inoculated now if your day time temperatures hang around 50°F or more for a few weeks after inoculation. If your locale is usually a snowy place in the winter, you can also cut trees now and store in a protected, shady place until inoculation in early spring. Growers in warmer locations that get just a little snow can cut and inoculate all fall and winter long!

Tree Dormancy: What and When is it?

An easy way to explain Dormancy is simply hibernation for trees. Dormancy minimizes a plant's interactions with the external environment when the temperatures drop into harsh conditions. Plants protect themselves by taking actions such as tightly closing buds to shield them from the killing cold and protect wood vessels from frost cracking. Trees go into dormancy in the fall of the year and early dormancy is visible by the first blushes of leaf color. Dormancy lasts until the weather warms enough to signal that nutrients can leave the sapwood to form twigs and leaves in the spring of the year. Usually once one third of the canopy has changed color it signals dormancy. This is a sign that all the interactive functions in the tree have shut down and it is now safe to cut the tree for mushroom wood.

Why does dormancy matter for Shiitake cultivation?

During dormancy transport of nutrition necessary for springtime growth has slowed and sugars are stored safely in the sapwood of the tree, making the wood a perfect food source for the hungry mushroom mycelium. During early dormancy wood cells are soft and easily penetrated by the mycelium. Once the shiitake mycelium establishes itself and temperatures drop below 40° F, the mycelium will also slow its growth and is protected in the wood structures throughout the winter months. You will want 3-5 weeks of daytime highs above 50°F for the mushroom mycelium to safely establish itself in the wood to weather the upcoming winter. Areas where the winter temps are usually above 40F during the day can expect to have some fungal growth throughout the winter.


Winter Storage Options (below 45°):
1. Choose to bring inoculated logs indoors to a heated building and manage logs for spawn growth there.
2. Hold the logs outdoors in a protected area, say, north side of a building or in a protected spot in the woods. Stack the logs low so they can be covered by snow. Inoculate these as soon as the earth starts to thaw in the spring.