How To Activate Your Mushroom Logs

How To Activate Your Mushroom Logs

Did you know that most of your mushroom logs must be activated before they can begin fruiting? This is commonly known as shocking. It is forcing your mushroom logs to start producing mushrooms. Mushroom logs that have been shocked tend to produce mushrooms faster than those that have not. 

Keep reading to learn how to activate your mushroom logs.

How to Activate Your Mushroom Logs 

Before shocking the logs, check for colonization evidence. It would be best only to shock your logs once they have incubated. Your mushroom spawn manufacturer will provide an incubation window to guide you in your log mushroom farming procedure.

You should see whitish mycelium growing star-shaped on the log’s ends. The mycelium should also be visible in the log’s cracks and the holes you drilled during inoculation. If the log is fully colonized, the log ends should be fully covered in mycelium. 

There are three main ways to shock mushroom logs;

Cold Water Immersion

The most popular way to shock your logs is to soak them in cold, non-chlorinated water for 12-24 hours. Any pool of water big enough to submerge the logs will do. Depending on the number of logs, you can use a bathtub, swimming pool, pond, or stream.

Vibration Shocking

You can shock your logs by dropping them on the ground or hitting the log ends with a rubber mallet. This will shock the mycelium due to the vibration created once the logs hit the ground or are hit with a mallet.

Rapid Temperature Change

A rapid rise and drop in temperature can force your mushroom logs to start fruiting. This is because the mycelium will translate the changes as a season change. Such as a switch from winter to spring. To do this, you can move your logs indoors and back outdoors.


  1. Not all mushroom strains respond to shock. Several Shiitake mushroom strains do not respond well to shock. These include Miss Happiness, Bellwether, Snow Cap, and Jupiter. Only Oyster and Shiitake mushrooms respond to shock.
  2. You should wait 6-9 months after inoculation to soak your logs in water. This is to ensure that the logs are fully colonized. Waterlogging may affect full colonization by some mycelium, such as Shiitake mushrooms, as they do not like high moisture content. 
  3. Shock your logs in spring or fall, as summer is too hot and winter causes mycelium to be dormant. 

Post Shocking Mushroom Log Care Tips

Do the following to help your mushroom log fruit fast;

  • Water your mushroom logs every three days after the shock has occurred. Do not overwater the logs to avoid rotting or invasion of slugs.
  • Cover the logs in a moisture-wicking fabric after shocking them to keep them well-hydrated as they begin fruiting.
  • Be gentle when handling and stacking the soaked logs, as their barks tend to be looser and may break off, leading to moisture loss.

How Do You Know Your Mushroom Logs Have Been Activated?

The shocked mushroom logs should start producing mushrooms in 5-14 days. This depends on several factors, such as the surrounding temperature. Additionally, the logs will start producing a mushroom smell when they are close to fruiting.

The mycelium on the log ends will also turn from white to a chocolatey brown color. Depending on the color of the mushroom spawned, you will also notice small white or brown bumps on the logs. These small bumps are the small baby mushrooms forming on the log.

Unconventional Techniques for Activating Mushroom Logs

Japanese mushroom farmers believe that lightning increases the mushroom yield. This folklore has influenced the research by Japanese Scientist Koichi Takaki, who tried to recreate the effect of lightning on mushroom logs by using high-voltage electricity.

The experiment proved that the rapid temperature rise led to the creation of shock waves within the logs that led to the activation of the mycelium. Takaki states that the shock vibration led to mycelium strand breakage, ultimately stimulating the fruiting process. 


This method is highly dangerous and should be attempted at your own risk, as the chances of being electrocuted are extremely high. The shock generated can travel beyond the log and potentially shock you if you are not wearing the right protection gear.