Mushroom mycelia colonizing bulk substrate with water droplets forming on top, and correct fresh air exchange makes the mycelium fluffy white

Why Temperature, Humidity, and Fresh Air Exchange (FAE) are important

Temperature, humidity, and fresh air exchange are all important factors to consider when growing mushrooms.


Temperature plays a critical role in the growth and development of mushrooms. Each mushroom species has its own optimal temperature range for growth, but generally speaking, most mushrooms prefer temperatures between 60-70°F (15-21°C). If the temperature is too low, the mushroom's growth will slow down, and if it's too high, it can inhibit growth or even kill the mycelium. High temperatures will also encourage the growth of unwanted mold species such as Trichoderma or cause the uncontrolled growth of bacteria colonies.

As a rule of thumb, slow and steady wins the race. If you are having trouble with high contamination rates, just lower the temperature by a few degrees. You may have slower mycelium running and colonization times, but this will ensure that your mycelium can keep the other contaminants in check.


Humidity is also crucial for mushroom cultivation, as mushrooms require a high level of humidity to grow. A relative humidity of between 80-90% is ideal for most mushroom species. If the humidity is too low, the mushrooms will dry out and stop growing, if it's too high it can cause mold growth.

Moisture content in the substrate is also an important factor to consider when growing mushrooms. The substrate, or growing medium, needs to have the right amount of moisture to support the growth of mushroom mycelium.

If the substrate is too dry, it can inhibit the growth of the mycelium, causing it to become stunted or even die. On the other hand, if the substrate is too wet, it can lead to mold growth, which can inhibit mushroom growth and lead to contamination.

The optimal moisture content for most mushroom species is between 60-70%. This can be achieved by mixing the substrate with water, and then draining off the excess water before inoculation.

To ensure that the moisture content remains at the optimal level, the substrate should be regularly monitored and misted with water as necessary.

Humidity and moisture are two sides of the same coin. If the humidity is too high, and there are many fluctuations in temperature throughout the day, the excess moisture will be taken up by the bulk substrate and overload the substrate with water content. Controlling humidity and regular air flow is important to find this balance.

Fresh Air Exchange

Fresh air exchange is equally important as it provides the mushrooms with the oxygen they need to grow and thrive. Fresh air stimulates pinning and the initial growth of the mushroom fruiting body. The amount of oxygen (O2) available in the air also dictates the morphology of your mushroom fruits. If you find that your mushrooms are growing in irregular shapes, try increasing the FAE.

In summary, temperature, humidity, and fresh air exchange are all key factors that must be carefully monitored and controlled during mushroom cultivation. Maintaining the optimal levels of each will ensure healthy and productive mushroom growth.

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.