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Introduction

Inoculating logs with species that are 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 life. Logs are slow to degrade, 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 mushroom by drilling holes into the log and filling them with either sawdust spawn or plug spawn (wooden dowels that have been inoculated with spawn). You then wait for the log to inoculate fully (usually several months) and once myceliated, it is triggered to fruit by a change in its environment such as water or temperature. Often, a spring/fall rain will be the catalyst to fruiting.

When and where to make your log

  • Best time of the year to cut your log is late winter when the trees are completely dormant or in early spring before they leaf out
  • Once cut, logs should be inoculated within a few weeks and no later than two months. The fresher the better!
  • The location and positioning of your log will depend on the species you are growing, but a general rule of thumb is a semi-shaded area with good airflow and exposure to rain. Remember these 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

Equipment

  • Freshly cut log (Diameter: 5 – 10 inches, Length: 2 – 4 feet)
  • Spawn, either
    • Plugs
    • Sawdust
  • Drill with bit
    • Plugs: 5/16 inch bit
    • Sawdust: 7/16 inch bit
  • Hand tools:
    • Plugs: mallet
    • Sawdust: inoculation plunger
  • Beeswax or parafilm
  • Paintbrush or wax dobber
  • Heat source and saucepan/small electric wok works well

Method

Step 1: Selecting the log

  • Log should be cut from a healthy living tree with no signs of other fungi and should not have been in contact with the ground for more than a month
  • Generally, logs should be between 5-10 inches in diameter and 2 to 4 feet long
  • The type of wood you use will depend on the local species of trees available to you and the species AND strain of fungi you want to grow. For example in general:
    • Oyster mushrooms: Beech, Elm, Maple, Oak, Poplar
    • Reishi: Alder, Elm, Maple, Oak, Willow, Hemlock, Pine, Spruce
    • Shiitake: Alder, Ash, Beech, Birch, Maple, Oak, Poplar, Douglas Fir

Step 2: Inoculating the log

  • Drill holes starting 2 inches from the end of the log
  • Holes should be spaced approximately 6 inches apart and in rows approximately 3 – 4 inches apart along the length of the log. (A diamond pattern)
  • If you are using plug spawn:
    • Use 5/16 inch bit to drill holes
    • Drill holes 1 1/4 inch deep
    • Tap the dowels into the holes with a mallet until flush or just below the log’s surface
  • If you are using sawdust spawn:
    • Use a 7/16 drill bit
    • Drill the holes ½ inch deep
    • Fill holes with sawdust using an inoculation plunger

Step 3: Sealing the log

  • Once all the holes are filled, the next step is to seal all open surfaces of the log with wax to keep the moisture in, keep wild fungi spores and bacteria out, and minimize critters from feasting on your mycelium
  • One way to seal the holes is with beeswax.  An alternative is parafilm
  • Melt the wax in a saucepan, the trick is to keep the wax warm throughout the process as it is very sticky and becomes brittle as it cools down. A great alternative I learned at a Fungi for the People course (https://fungiforthepeople.org/) was to use an old electric wok. It kept the wax liquid throughout the process and provides the perfect shape for dipping the ends of the logs into
  • Paint melted wax over each hole as well as the ends of the logs (by dipping it right in the saucepan/wok), and anywhere the bark is nicked or branches are cut off to help minimize competition with wild fungi.  This also helps prevent moisture loss

Step 4: Labeling the 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
    • wood type
    • date

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)
  • 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 to minimize the growth of contaminants
  • Monitoring your logs to ensure they don’t dry out or crack. If you are not getting enough rain to keep the moisture levels (has not rained for 2 weeks or so), you can water them with a sprinkler or dunk them in water. Make sure that the bark dries out before between soakings
  • 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 will take several months to over a year to 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
  • After soaking, stack the log 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
  • During the growing season, the resting/fruiting cycle can be repeated several times

Notes

  • 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 very time consuming
    • 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!
    • Our first experiments with this technique failed
Last Updated On March 23, 2018

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