Here’s how to regulate humidity when growing mushrooms

When growing magic mushrooms humidity is crucial. Without the right moisture balance, your mycelium can dry out or become contaminated. In this article you’ll learn how to regulate humidity optimally, from handy devices to practical tips per growing stage.

Mushrooms are fungi that rely heavily on humid conditions. This includes, for example, the mycelium, which is the network of fungal threads from which the mushroom grows. It can remain active if the humidity is continuously between 85 and 95 percent. Too high humidity without adequate circulation promotes fungal or bacterial growth, which can destroy the culture. On the contrary, too low humidity can lead to slow growth, dehydration and/or malformed fruiting bodies. This is what Paul Stamets wrote about in his interesting book called Growing Gourmet and Medicinal Mushrooms, a mustread for all growers.

The importance of stable humidity when cultivating mushrooms has been detailed in several scientific publications on mycology and fungal biology. For example, Stamets and Chilton state in The Mushroom Cultivator that a relative humidity of 90-95% is essential during substrate colonization, while a slightly lower humidity (85-90%) is desirable during fruiting to prevent condensation and bacterial growth (Stamets & Chilton, 1983).

In addition, a study published in the journal Fungal Biology shows that inconsistent humidity leads to abnormal fruiting bodies and an increased risk of contamination, especially in species such as Psilocybe cubensis (Chang & Hayes, 2013). These findings highlight the importance of using hygrometers and controlled ventilation to keep the environment constant.

Sources:

• Stamets, P., & Chilton, J. S. (1983). The Mushroom Cultivator: A Practical Guide to Growing Mushrooms at Home. Olympia, WA: Agarikon Press.

• Chang, S.T., & Hayes, W.A. (2013). “ Influence of environmental factors on mushroom fruiting and morphology. .” Fungal Biology, 117(3), 211-219. [DOI link when available]

So you need to properly regulate humidity when growing mushrooms, in which the following devices and methods can help:

1. Humidifiers: Ultrasonic and cold mist humidifiers are effective in increasing humidity. It is important that the mist not be directed directly at the mycelium to avoid water accumulation, which can cause fungal diseases.
2. Hydro or hygrometer: With a digital hygrometer you can accurately monitor humidity. A sensor that measures both humidity and temperature is ideal so you can make quick adjustments.
3. Ventilation: Ventilation is crucial. Without circulation, the air around the mycelium can become too moist, causing condensation. Therefore, a small fan can be a good addition. According to Miles and Chang this distributes moisture evenly without drying out the air.
4. Atomization: In small culture setups, manually atomizing water with a plant sprayer can be effective. However, this requires close supervision to prevent the substrate from becoming too wet.

You do well to adjust humidity when growing mushrooms based on their phase. For example, in the mycelium stage, a humidity of 90 to 95 percent is better. This is because mycelium grows rapidly under constant humidity. Make sure condensation is avoided by light air flow. For fruiting bodies, humidity is better between 85 and 90 percent. This stimulates mushroom formation. It is crucial that humidity remains stable, as large fluctuations can cause growth arrest.

So it is also important to keep the humidity constant, which these tips help with:

1. Use an enclosed grow box: a small enclosed space, such as a grow box, filter box or terrarium, helps keep humidity stable.
2. Check regularly: daily checking of hygrometer and condensation points prevents problems from being noticed too late.
3. Place water bowls: in an enclosed space, water bowls increase humidity through evaporation. Combine this with a fan to prevent stagnation.
4. Use moisture-absorbing materials: sometimes adding moisture-absorbing substrates or spongy materials helps to absorb fluctuations.

Common mistakes when regulating humidity for growing mushrooms

Unfortunately, especially novice growers regularly make mistakes when they want to regulate the humidity in the room in which they, for example magic truffles grow. This can cause the cultivation to fail completely, which of course would be a shame. Therefore, make sure you avoid the following mistakes:

• Overwatering: the mycelium can drown due to excess water. It also allows bacteria to grow.
• Temperature and humidity not in balance: mold can rot with high humidity when the temperature is too high.
• No air circulation: stagnant air promotes contamination, which of course you don’t want.

By following the above tips and properly monitoring humidity, you will increase your chances of a successful and healthy grow!

Disclaimer: This article is intended for educational and scientific purposes only. The cultivation, possession or use of psilocybin-containing mushrooms is regulated or illegal in many countries, including the Netherlands and Belgium. Always consult local laws before engaging in any activities with these mushrooms. The author is not responsible for any illegal application of the information in this article.