Monitoring Moisture
To determine if your logs are losing too much water, weigh at least one average size log immediately after inoculation:
1. Mark that log with paint or a tag.
2. Weigh the log, and record the weight.
3. Reweigh the marked log(s) every week. To determine weight loss, use this formula:
((Original log weight - Current log weight)/ (Original log weight)) x 100 = % moisture lost.
If your answer is greater than 10 percent, you will need to mist or water your logs more often. As the mycelium grows and uses up the nutrients, the log will naturally lose weight.
To reestablish a new "base weight" or to replace the "original log weight after inoculation," you will have to reweigh your log every 6 months. To obtain a new "original log weight:"
1. Soak the log for 48 hours.
2. Remove it from the water and allow it to drain for 24 hours.
3. Weigh the log. This weight will be your new base weight.
Many shiitake gardeners learn to "feel" the moisture in their logs just by picking them up. If they seem light, then they know they have not applied enough water.
Unless you are going to fruit your logs, it is best not to soak the logs
to restore moisture. Soaking the logs at the wrong time can cause a break
in the mycelium growth cycle and prolong the time from inoculation to fruiting
or between fruitings.
Keeping The Logs Moist
You can use lawn sprinklers, misters, or a greenhouse mist system to
keep the logs moist. Logs should be given a fine mist from 8 or 9 in the
morning until 6 or 7 in the evening during the heat of the summer. If you
are using a lawn sprinkler, watering this long will cause the bark to fall
off of the logs. Lawn sprinklers can be turned on for about 4 to 5 hours
in the heat of the day. There is no need to water or mist your logs if they
are outdoors and it is raining. During spring and fall, when the temperatures
are below 80 degrees F, you can water less often. If you plan to fruit logs
in the winter, water them weekly.