Mushroom Plugs - Caring for Your Logs

In our Mushroom Plugs video, Tricia demonstrated how to select, prepare and insert the mushroom plugs into a log or stump. The plugs and ends of the logs are sealed with wax and allowed to harden. Now the logs will need to be positioned for incubation or spawn run. This is the spreading of the fungus throughout the sapwood in the log. This process can take from 6 to 18 months, depending on the fungus strain, the growing conditions in the log, and the air temperature.

Setting Up the Laying Yard

The location you select is very important. First choose a shady area, preferably under pines or other conifers and it should be protected from the wind. If you cannot find enough shade, 80% shade fabric can be used. If an outdoor location is not feasible, the logs can be stored in a cool garage, root cellar, barn or shed. Second, the logs must be kept moist, so access to water at the laying yard is very important.

The logs should not be in direct contact with the soil, so place the inoculated logs on another log, a cinder block or a wood pallet. Also, if using more than one variety of mushroom plug, keep the logs separate to minimize cross-species competition.

Arrange the logs in a criss-crossed pattern until you have a "pile" of logs. The pile is referred to as a "rick stack" or "crib stack". This arrangement will help conserve moisture and space. Another arrangement is called the Japanese Hillside Method. As the name implies, this method is used in areas with steep hillsides. stacked mushroom logs

photo from

Keep The Logs Moist

The logs need adequate moisture to support the growth of the mushroom mycelium. The desired moisture level should be between 35-55%. If the moisture level drops below 25% the mycelium will begin to die off. If you live in an arid region, the logs will need to be watered to maintain adequate moisture. A sprinkler system or misters can be used to provide moisture.

While it is important to keep the logs moist, don't keep them wet all the time. It is important to allow the bark to dry out to avoid contamination from "weedy" fungi.

Using a reference log is an easy way to monitor moisture content in the log. Choose a log (or two) that is representative of the logs you are using. Weigh the log as soon as possible and label with a tag in order to track it. Inoculate along with the other logs but use this log throughout the incubation period to estimate the moisture content. For complete directions on using a reference log check out Producing Shiitake Mushrooms–A Guide for Small-Scale Outdoor Cultivation on Logs.

Now it is Time to Wait!

The logs will take from 6 to 18 months before colonization is complete. The size of the log, type of wood and species of the mushroom will determine the time frame. During the waiting period, the log's moisture will need monitoring. Keep an eye on the end of the log. A characteristic "mottling" is the signal that the log is ready to produce fruit. The area of mottling should cover at least 65% of the cut end. If not, wait a bit longer.


  • Hayley, well we had some problems with the logs that we inoculated so there is not a follow up video or article.

    Suzanne at
  • Thanks, it just says at the end of the article “Coming Up…Initiating Your Logs and Harvesting” and this one was so informative o thought I’d check.

    Hayley Schultz
  • Hayley, this is the only article we have on mushroom plugs. We also have a video that shows you how to start a mushroom log.

    Suzanne at
  • Hi where is the article on ‘initiating your logs and harvesting’? I can’t seem to find it.


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