- Log Mushroom Cultivation FAQ
Log Mushroom Cultivation FAQ
Log selection & maintenance
What type of log is best for growing mushrooms?
Some mushrooms are generalists, meaning they’ll grow on a wide variety of substrates, while others are specialists, preferring just a few. You can reference the chart below to find which tree species work best for each mushroom variety, and other types of wood they can be grown on. Preferred species will offer higher success rates, greater yields, and produce longer. Other types of wood can support mushroom growth but may have varying results in yield and length of production.
Most mushrooms grow on hardwoods, some species better than others. Generally, oak and maple perform well across the board. Their dense wood offers a lot of nutrition for a longer, sustained fruiting period. Softer hardwoods like poplar or aspen will myceliate faster and produce mushrooms sooner, but may not yield as much or produce for as many years. With that being said, oyster species love soft hardwoods like aspens and poplars!
Check out our blog for more specific information: Which Tree Species Is Best?
What size should the logs be?
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.
Should the wood be old or freshly cut?
Only freshly cut, disease-free wood should be used. Old or rotting wood should be avoided as it will likely contain contaminant fungi or be too dry to support mushroom growth. Once cut, the sooner you can inoculate the log the better, though you can wait up to 4 weeks after cutting before inoculating the log. When temperatures are consistently below freezing, the inoculation window can be extended for several months by covering freshly cut wood with snow to maintain moisture until you are ready to inoculate in early spring.
When do I cut the logs?
Healthy, living trees can be felled for mushroom bolts nearly any time of year. It is not recommended to harvest logs during the spring between budding and full leaf out. During this time, most of the nutrients and energy of the tree are expended in a push to develop flowers and foliage, leaving little for fungal growth. Also, bark is loose, increasing the risk of damage during cutting. Intact bark is very important for the spawn run. Never cut dead, dying, or diseased trees for mushroom growing.
Timing log harvests with sap flow can help increase the yield and longevity of your mushroom bolts. This typically coincides with dormancy cycles. Two ideal times for harvest are: during the fall, after ⅓ of tree leaves have changed color through leaf drop and in late winter to early spring before bud swell and leaf out. These are both times when sugary sap in the tree will be concentrated in the wood, providing nutrients for mycelial growth, and bark should be tight reducing the risk of slippage.
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.
We recommend sourcing logs from a sustainable forester or using sustainable practices in culling trees for mushroom production.
How often should I water my logs?
It’s important not to let the log dry out but it’s also important not to over-water the log. Logs should be stored in shady outdoor locations close to the ground. In temperate climates, they generally retain enough moisture to colonize fully without watering. During especially dry years, droughts, and in arid climates, watering may be necessary. Most of the time though, no supplemental watering is needed.
It’s okay to water the log to force it to fruit but most growers wait until the log fruits once naturally before beginning to shock them into fruiting. Logs shouldn’t stay wet on the outside for long periods of time. Frequent light watering can even damage logs and cause contaminant growth. Long periodic soaking is the preferred method of renewing water content should your logs appear dry or lose vitality.
Any other tips for selecting logs?
Trees with more sapwood than heartwood may produce bigger flushes of mushrooms, especially in the case of shiitakes. Often, the sapwood section of a tree is thicker on trees with vigorous growth in open canopies rather than shade-grown trees.
Can I soak my logs to force them to produce mushrooms?
Force fruiting works best with shiitake mushrooms. We recommend soaking your logs overnight and not more than 24 hours. You should allow your log to fruit once naturally (after a rainfall or other triggering event) before attempting to force fruit your log. Allow at least one month of rest before attempting to force fruit again.
Can I allow the log to freeze over winter?
Yes, logs will be fine in outdoors in the winter. A blanket of snow will help to protect the logs from drying out.
Inoculation & supplies
Do I need to pre-prep the logs ahead of time of inoculation?
When should I inoculate my logs?
Logs should be inoculated within a week or two 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. You should not use logs that were cut last year or logs with damaged bark. A month would be about the longest reasonable stretch of time between cutting and inoculating.
What tools do I need?
For plug spawn, you’ll need a drill with a 5/16” (8mm) bit to make holes in the log, a hammer to drive the plugs into the holes and wax to seal the holes. If you are inoculating several logs, you may find that an angle grinder adapter with an 8.5mm drill bit will help the work to go more quickly.
For sawdust spawn, we recommend a drill with a 7/16” (12mm) drill bit and an inoculation tool to pack the sawdust into the holes. If you are inoculating several logs, you may find that an angle grinder adapter with an 12mm drill bit will help the work to go more quickly. You can insert sawdust into the holes by hand but an inoculation tool greatly speeds up the process and allows the sawdust to be packed more densely increasing the success of log inoculations.
All of the holes need to be sealed with hot wax (cheese wax, food grade paraffin wax, beeswax etc…) to prevent them from drying out and to seal them off from contamination.
How much spawn do I need?
You can use this log inoculation calculator to help you figure out exactly how much spawn you'd need, depending on the size of the log and hole spacing.
For the totem method, one 5 lb. bag of sawdust spawn should be enough to inoculate three or four 10-12" stacks.
How do I choose plugs vs. sawdust?
Plugs are very resilient but are slower to colonize. Plugs require only a drill and hammer for tools, and are economical for smaller projects. Sawdust colonizes drilled logs about 30% faster than plugs. They're good for larger projects, but an inoculation tool is required, along with other tools if you'd like to speed up the project. The totem method, using sawdust, is good for urban settings or other locations without access to a forested or shady area. No special tools are needed.
Harvesting & yield
How long will it take from the time of log inoculation to harvest?
That will depend on what species you’re growing, the size of your logs, and environmental conditions. Most mushrooms on standard size logs in temperate climates will take about a year to fully colonize before they fruit. This can vary between 6 months to two years. Smaller diameter logs and soft hardwoods will typically fruit sooner, though they’ll have less longevity.
Often, mushrooms need cool weather and moisture to fruit. Growth slows in the heat of the summer. If you inoculate in the spring, you might get your first flush of mushrooms in the fall but most likely it will take a full year until you see your first fruiting. If you inoculate in the fall and are able to keep the mycelium from going dormant, you may get mushrooms as soon as the next spring, though more likely the following fall.
What kind of yield can I expect?
The general rule of thumb is one year of production per inch of log diameter. However, yields will vary greatly depending on the mushroom strain, tree species used, and environmental conditions each season.
Shiitake logs usually have their largest flushes during their second and third years producing. A good yield per log is ¼ - ½ pound each flush, with 2-3 flushes per season.
How long does it take for me to get my first flush of mushrooms?
First fruitings are variable, but you should expect to wait at least a year for most of the species to fully colonize their logs. After they begin to fruit the logs may produce for up to a year per inch of diameter of the logs.
How many years will a log produce mushrooms?
Two to four years, on average; varies by type of wood, size of log, whether or not it's forced, rainy/dry balance, etc.
What kind of pests can I expect on my mushrooms?
Some mammals like deer or squirrels may take a nibble out of the mushrooms, but generally, they don’t devastate a crop. Occasionally, you may find some insect or slug damage. Just cut out that part of the mushroom. The rest will be fine.
Will hemlock work for the Reishi?
There are two types of Reishi commonly cultivated in the US: Ganoderma lucidum and Ganoderma tsugae. Only Ganoderma tsugae will grow on hemlock.
Can Wine Cap be grown using drill or totem methods?
No, the Wine Cap only grows on substrate that is already broken apart, like sawdust. It's best in garden path areas or other places where beds of sawdust, wood chips or straw can be maintained.
How do you cultivate Hen of the Woods?
Hen of the Woods should be inoculated in oak logs. After the one-year incubation period, where you stack logs in a normal fire-wood style stack, you should bury your log under 1-2 inches of soil. Bury them someplace shady where they will have access to water or rainfall. Make sure to mark the spot where your log is buried and keep an eye for Hen of the Woods mushrooms sprouting from the soil throughout the year (it usually fruits during the fall).
Are cultivated mushrooms the same size as their wild counterparts?
How long can I store plug and sawdust spawn?
Plug and sawdust spawn will store for six months to a year in a refrigerator. The fresher the better, but mycelium is pretty resilient. If you don’t get around to inoculating right away, tuck it away in your refrigerator until you’re ready.
Mushroom spawn will naturally develop a layer of white mycelium (or yellow for Chicken of the Woods). This is totally normal and indicates healthy spawn. Break up your spawn bags thoroughly before use. And be sure to use logs cut within 4 weeks of inoculation.
What if I buy spawn and can't get around to inoculating in the spring?
Unless otherwise noted, you can store the spawn in the fridge until you’re ready. We recommend waiting no more than a few months. Just be sure to inoculate your logs within 4 weeks of cutting them. We recommend avoiding log harvest in the spring between bud well and full-leaf out, since nutrients are directed toward flower and foliage growth and bark is loose. See our section about best time to harvest logs for more info.
Is my spawn moldy? What is this white or yellow substance?
Mushroom spawn will naturally develop a white (or yellow for Chicken of the Woods), mold-like layer called mycelium. This branching network of threads is the primary body of fungi, the vegetative structure. A good analogy is if a mushroom is like an apple, then mycelium is like an apple tree. Seeing mycelium grow through your bag is normal and indicates healthy mushroom spawn. If your spawn looks green or black, the culture may be contaminated and should be discarded. You can reach out to us for confirmation.
In the following images, you’ll see healthy spawn plugs with different amounts of mushroom culture visible. The first photo shows plugs with minimal mycelial growth. They are completely fine to use and not any less 'potent'. Over time the mycelium will continue to grow and envelop the plugs as seen in the second photograph. This is also normal and doesn't change how the plugs are used, though you may need to break up the plugs within the bag before use to separate them from the mycelial mass. Don't open the bag; simply squeeze it to break up the mycelial mass. The third photo is the same plug bag after it has been broken.
Often, mycelium is broken up in shipping, so it can appear less myceliated. Let it sit for a few days and it should bounce back.
What are the little 'dots' that I am seeing in my plug spawn bags?
Millet! We grow out our mushroom cultures on a mix of nutrient-rich grains to help them transfer onto wood. They are totally normal and can be ignored in your inoculation process.