Inoculating a mushroom log with plugs
Inoculating logs with species that are generally primary decomposers such as Shiitake, Reishi, Lion’s mane, Turkey Tail or Oyster Mushrooms, is a relatively low maintenance way of incorporating edible fungi into your backyard or wood lot. Logs are slow to decompose, thus once you have put the initial resources and time to inoculate them, they will provide several years of mushroom yields with minimal maintenance. The basic idea is to inoculate the log with your desired fungi by drilling holes into the log and filling them with plug spawn (birch dowels inoculated with mycelium). Once inoculated, you seal the plugs, log ends and any exposed area where the bark is missing with wax to seal in moisture, and to try to keep out wild fungi and bacteria. You then wait for the log to myceliate fully (4 month to 2 years depending on mushroom species, wood species and log size) and once myceliated, it is triggered to fruit by a change in its environment such as moisture level or temperature. Often, a spring/fall rain will be the catalyst to fruiting.
When and where to make your log
- The best time of the year to cut your log is late winter when the trees are dormant or in early spring before they leaf out.
- The trees you are felling should be healthy (disease free) with their bark relatively in tact. This will give the fungi you want to grow the upper hand over all the wild spores and bacteria competing for this food source.
- Once cut, logs should be inoculated within a 1 to 6 weeks. The fresher the better to minimize the opportunity for competeing wild fungi and bacteria to colonize your log.
- The location and positioning of your log will depend on the species you are growing, but a general rule of thumb is a full to semi-shaded area with good airflow (but protected from the wind) and exposure to rain. Remember the fungi species you grow using this technique are primary decomposers and are naturally found in areas with dead trees and woody debris, such as a forest or woodlot, so think about placing them in an area that simulates those microclimatic conditions.
- Freshly cut log (Diameter: ~ 3-10″, Length: ~3-4′)
- Mushroom spawn plugs (~50 plugs per log depending on size)
- Drill and 5/16″ (8.5mm) drill bit (Bard-point drill bit for use in a low speed drill (under 2500 rpm).
- Stop collar for drill bit (optional)
- Rubber Mallet
- Beeswax or soy wax (~ 1 pound will cover ~ 12 logs depending on size)
- Paintbrush or wax dobber
- Heat source and saucepan/small electric wok or slow cooker works well
- Surface suitable for drilling logs (e.g. 2 saw horses with boards to place log on)
- Labels and marker (Aluminum log tags & ball point pen, flaggin tape & oil based marker)
Step 1: Select the Log
- Log should be cut from a healthy living tree with bark intact and no signs of other fungi or disease.
- Generally, logs should be between 3- 10″ in diameter and 3-4′ long.
- The type of wood you select will depend on the species of trees available and the species AND strain of mushroom you want to grow. For example the following mushroom species will generally grow on these tree species:
- Pearl Oyster (Pleurotus Ostreatus): Alder, Aspen, Beech, Birch, Cottonwood, Elm, Maple, Oak, Poplar
- Lion’s Mane (Hericium erinaceus): Alder, Aspen, Chestnut, Cottonwood, Elm, Maple, Oak, Tulip Poplar, Walnut, Willow
- Reishi (Ganoderma lucidum): Alder, Aspen, Cottonwood, Elm, Maple, Oak, Poplar, Willow
- Shiitake (Lentinula edodes): Prefers Oak but can try Alder, Ash, Aspen, Beech, Birch, Chestnut, Cottonwood, Elm, Ironwood, Maple, Poplar
- Turkey Tail (Trametes versicolor): Alder, Ash, Aspen, Beech, Birch, Chestnut, Cottonwood, Ironwood, Maple, Oak, Poplar, Willow and some strains will grow on conifers
Step 2: Inoculate the Log
- Wash your hands and set up your work station including heating up the wax.
- If you are using a stop collar on your drill bit tighten it to allow you to drill 1¼”.
- Drill a row of holes along the length of the log 1¼” deep and 4-8″ apart.
- Rotate the log and drill a second row of holes staggered relative to the first row. The distance between rows should be ~2-3″.
- Continue to rotate drill rows of holes to form a diamond pattern covering the entire log.
- Tap the plugs into the holes with a mallet until just below flush with the bark.
Step 3: Seal the log with wax
- Once all the holes are filled, seal all open surfaces of the log with wax including your plugs, the ends of the log, any breaks the bark and places where branches have been cut off.
- This is done to keep the moisture in, keep wild fungi spores and bacteria out, and minimize critters from feasting on your mycelium.
Step 4: Label log
- Make sure to label your logs so you can learn from you experiments. Use a weather resistant tag and label it with the following:
- Mushroom species and source (e.g. fungi akuafo)
- Wood type
Step 5: Establishment Phase
- Place your logs in a shady, moist location away from the drying effects of the wind and direct sunlight. Ravines, close to streams or water bodies are good locations to keep your logs, or if you don’t have any natural canopy cover, you can stack them under a shade cloth or on the north side of a building (but be sure that they are not protected from the rain by the eaves as they need the moisture to not dry out).
- If logs were cut down more than 10 days before inoculation, you should soak them in cold non-chlorinated water between 12 and 24 hours (but no longer). Otherwise, logs don’t need immediate soaking and can be placed right away in a moist shady area for incubation.
- Regardless of where you place your logs, ensure that they are in a location and loosely stacked in such a manner that there is enough ventilation among the logs (2-3″) to minimize the growth of contaminants.
- It is important to monitoring your logs to ensure they don’t dry out or crack by keeping the moisture inside the log high while allowing the outside of the log to dry out so the bark does not rot or fall off. If you are not getting enough rain to keep the moisture levels and humidity high (has not rained for over a week, humidity is below 50%), the best way to hydrate your logs is to either soak them in cold water between 12 and 24hrs or water them (sprinkler) for several hours once or twice a week rather than for 5-10 minutes every couple of days. Make sure that the bark dries out before between soakings.
- You can help the logs to retain moisture by covering them with burlap or shade cloth that allows for airflow and the rain to get through. Avoid covering with plastic as it can encourage mold and bacteria to grow.
- Some species, including Reishi and Turkey Tail, prefer to have the log in contact with the ground by either fully burring the log or by “planting” the log vertically in the ground in the direction that the tree would have grown.
- Logs can take 4 months to 2 years incubate (become fully myceliated) depending on your climate, the mushroom species and strain, the log size, quality, density and tree species. Be patient!
- Check your logs after a good soaking of rain and if the ends are white with mycelium this is a sign that the spawn run (myceliation) is nearly done!
Step 6: Maintenance and Harvest
- Flushes of mushrooms are often triggered by moisture and cooler temperatures. You can induce a flush by soaking your log in cold water for 24 hours
- For shiitake logs, after soaking, stack the logs upright on a fence or side of a building
- If it is fully myceliated, mushrooms will appear in a week or so
- If not, lay it back down to incubate for another few months
- After the first flush has been harvested, the log should be laid to rest for 6 – 8 weeks and then soaked again to trigger another flush
- Depending on the length of your growing season, the resting/fruiting cycle can be repeated several times
- If you live in a forested area, you have very little time to inoculate your logs. Wild fungi are abundant in forested areas and will be quick to colonize the newly felled tree!
- A drill bit with a stopper is a valuable tool if you are going to do lots of these. We have purchased ours from http://www.fieldforest.net/ If we get enough interest, we can bulk order this tools and import them into Canada
- http://www.fieldforest.net/ also sells the inoculation plunger for sawdust spawn and wax dobbers
- We have not purchased from this company but they also sell these tools: https://www.mushroompeople.com/products-page/log-cultivation-supplies/
- If you use beeswax, whatever container you use to heat the beeswax will never come clean again. Ensure what you are using is not your favourite camping pot…
- We use oil based markers with flagging tape to mark our outdoor experiments. Regular Sharpie pens will fade very quickly. Other alternatives include cooper tags that you write by creating indents in the metal. We also create maps of where we place our logs so that we have a copy of our experiments in a digital format
Fungi Akuafo Experience
- Drilling holes in logs and covering them with wax is extremely time consuming. Plan for significantly more time than you think you will need! A worker bee is a good idea to get extra hands to help
- Poplar trees are very heavy – ensure you have a plan for how to move them
- Overall, this is not our favourite technique. Why:
- This technique is more time consuming than building stacks
- This technique requires specialized tools
- We found critters pulled off the wax and then removed the sawdust spawn… not sure which critters, but they were busy