Shiitake Log Management 2017

The logs available from us were inoculated with a wide temperature range shiitake mycelium in spring 2017. They will fruit in 2018.  They should be kept stacked in the shade under the forest canopy, off the ground in a ‘log cabin’ style pattern or other pattern that allows free ventilation around each log until early spring 2018. At this point the logs should be stood on end for harvesting; one end on the ground and the other resting in a line on barbed wire strung between poles or trees or in a tepee arrangement around a pole or tree, or in ‘lean-to’ arrangements that allow free access to the logs for harvesting.

Note that we are now advising all of our customers to wait until a ‘natural fruiting’ has been initiated by environmental factors including light/daylight length, temperature, and rainfall/moisture before initiating fruiting by soaking. With the proper handling should give you 4-5 years of production depending on management regime.   The logs will produce mushrooms outdoors from May to November, they can also be fruited in a greenhouse during the winter months.  The length of life of a log is a factor of wood density and bark integrity and how intensively the log was managed.  Intensive management is a regime of soaking and ‘forced fruiting’ every 8 weeks during the harvest/growing season.

Briefly, shiitake is a saprophytic mushroom, that survives by breaking down the wood in the logs with enzymes and using it as food. The mushroom organism (mycelium) which was introduced into the log last year has been busy at work establishing itself in the sapwood under the bark of the log. After it is established in the sapwood layer it has gathered enough nutrients to try and reproduce itself, given the proper environmental stimuli. The mushrooms that the mycelium will produce are its means of reproduction. They are the fruiting bodies of the organism, like the apples on a tree. They carry the reproductive spores, which upon maturation will be released to the wind. They are also quite a treat to eat and of course it is intended that the mushrooms be harvested well before sporulation occurs.

The most important facts to remember are that the mycelium is adversely affected by lack of moisture inside the log, and by high temperature. To prevent those things from happening the logs must be kept in the shade and must be prevented from drying out inside. Shade can be natural, as under trees or bushes, or man-made such as burlap tarp or branches. Dehydration can be prevented if there is enough rainfall on the logs; otherwise it is necessary to manually water them by sprinkling for 12 to 24 hours continuously or by soaking overnight, submerged. The integrity of the bark must also be maintained. The bark is like the skin of the log, it keeps moisture in and other organisms out. The logs should be handled with care especially as they age and the bark becomes more fragile. The outside of the log must be allowed to dry between soakings to prevent molds from growing. Therefore the logs need to be in well ventilated area and not in standing water such as a swamp. Note that shiitake do not thrive in continuous wet conditions – the stimulus for fruiting involves more than one factor but rainfall/soaking is a key factor.  Ideally your logs should be stood, with one end on the ground, leaning against a tree, or you can string a rope or wire between two trees or posts and lean the logs on that. This prevents the mushrooms from getting squashed or dirty when they come out and lets the log absorb some moisture from the ground and from rainfall.

Generally a log will fruit spontaneously in the spring following an intensive rainfall. To get larger and predictable fruitings the logs can be “forced”. Note again that we are advising that you wait until a ‘natural fruiting’ has occurred before starting to ‘force’ the logs.  This forcing is achieved by soaking the log in cold water. Soaking by submerging the whole log in cold water for 6-18 hours (older logs require less soaking as they are more porous) is the best way to achieve this. However continuous irrigation with a sprinkler for about 24-48 hours also works. At the same time the logs can also be “shocked” to help induce fruiting. This is achieved by moving the log if you soak them, or if you sprinkle your logs you can drop the log to the ground and then pick it back up before sprinkling.  Some growers hit the logs with a hammer.  The logs should be turned end over end periodically as well.

Approximately a week after an intensive rainfall event or after soaking or irrigation the logs will start to “flush” with mushrooms. From the time you see little mushroom pins coming out, to maturity depends on the ambient temperature. Spring and fall are usually slow, summer fruitings can mature in a couple of days. The mushrooms should be harvested shortly after the veil has broken under the cap revealing the gills. After the harvesting the logs should be left alone so the mycelium can re-energize itself. This means six to eight weeks rest, then the soaking can be repeated. Three to four harvests can be produced in one season producing in total 1-2 kg. of mushrooms. Less frequent soakings thus allowing the mycelium to store more nutrients will generally produce larger mushrooms.

The total yield from each log will be about 8 lbs or 4 kg.

The above is a very short description of the process. If you are interested in more in-depth information the following books in our catalogue are excellent:


Growing Shiitake Mushrooms in a Continental Climate by  Kozak,M. &  J. Krawcyk   ($30.00)

Shiitake Grower’s Handbook by Przybylowicz,P. &  J.Donaghue  ($35.00)

 These books may no longer be in print or may be difficult to obtain, and are quite expensive.  An excellent source for updated and detailed information about mushroom cultivation outdoors on hardwood logs is the Cornell University website.  Here is the link to their interactive website with information about log inoculation and management:

The website has videos and a 56 page manual titled “Best Management Practices for Log-based Shiitake Cultivation in the Northeastern United States” that you can browse and download for free.

For more information contact us