Why is Humidity Important When Growing Mushrooms?

Humidity is a critical factor when growing mushrooms because it directly affects the mushroom's ability to develop and produce a successful crop. Here are some of the key reasons why humidity is important in mushroom cultivation:

  1. Hydration and Growth: Mushrooms are composed primarily of water, typically comprising 80-95% of their total weight. Maintaining adequate humidity levels in the growing environment is essential to keep the mushrooms adequately hydrated. When humidity is too low, mushrooms can dry out and fail to grow properly. On the other hand, excessively high humidity can lead to issues like mold and bacterial contamination.

  2. Spore Germination: The life cycle of a mushroom begins with spore germination. Proper humidity levels are necessary for the spores to absorb water and initiate the growth of mycelium, which is the thread-like structure that eventually develops into the fruiting body (the mushroom). Inadequate humidity can hinder spore germination.

  3. Mycelium Growth: Mycelium, the vegetative stage of the mushroom, requires a high level of humidity to grow and spread through the substrate (the material on which mushrooms grow, such as straw, logs, or compost). Optimal humidity conditions help the mycelium colonize the substrate efficiently.

  4. Primordia Formation: Once mycelium has colonized the substrate, the next step is the formation of primordia, which are small, pin-like structures that develop into mature mushrooms. Adequate humidity levels are essential for primordia formation, as they need a humid environment to develop properly.

  5. Mushroom Development: As the primordia continue to grow into mature mushrooms, maintaining the right humidity is crucial for the development of the fruiting bodies. Mushrooms require a stable humidity level to expand their caps, elongate their stems, and reach their full size.

  6. Preventing Drying Out: Low humidity can lead to mushrooms drying out and becoming stunted or deformed. This not only reduces the yield but also affects the quality of the mushrooms produced.

  7. Controlling Contamination: Proper humidity control can help prevent contamination by mold and bacteria. These contaminants can thrive in overly wet or overly dry conditions, potentially compromising the mushroom crop.

Different mushroom species may have specific humidity requirements, so it's important to research and understand the particular needs of the mushrooms you are cultivating. Many mushroom cultivators use tools like humidifiers, fans, and environmental controls to maintain the appropriate humidity levels within the growing environment. Maintaining the right humidity is essential for successful mushroom cultivation and can significantly impact the quality and quantity of the harvest.


We have an assortment of All-In-One Mushroom Grow Bags aka "Fun Bags' for your growing pleasure. Fun bags are literally a window into how mother nature produces mushrooms right inside the bag. 

Our fun bags are a great family or school project. Teach kids how to grow their own mushrooms and they will never go hungry. No yard needed. Grow right indoors from beginning until harvest. Bags can also be grown outdoors. 

These bags to not contain spores or liquid culture. Inoculate with your favorite mushroom spores or liquid culture. 

If you have any questions or need advice please contact us.