Why Is FAE Crucial for Mushroom Growth?
Fresh Air Exchange (FAE) is the process of removing stale and stagnant air from your mushroom growing environment. It is one of the most important factors in successful mushroom cultivation.
Maintaining humidity, temperature, and FAE is a crucial balance for successful fruiting. When not properly managed, these conditions can quickly deteriorate. The right equipment maintains ideal humidity and airflow through passive, natural means.
Improved Mushroom Growth
While many mushroom cultivators understand the importance of temperature, humidity and light for optimal fruiting, fewer are aware that fresh air exchange is equally critical. Mushrooms, like all living organisms, require a delicate balance of nutrients and conditions to thrive. The mycelial network, the fungus’ underground ‘roots’ system, requires a nutrient-rich substrate, a steady supply of oxygen, and a carefully controlled environment to achieve its optimal growth. Achieving these requirements isn’t easy, but it becomes even more difficult without proper ventilation.
Mushrooms need fresh air for respiration and produce carbon dioxide as a byproduct. High concentrations of CO2 hinder mushroom development, resulting in poor morphology and small caps. FAE provides a constant stream of fresh, oxygen-rich air that helps reduce CO2 levels and promotes healthy mycelial growth.
Aside from improving mycelial growth, FAE is also essential for maintaining a healthy substrate. Insufficient air circulation leads to dry substrates, which are less hospitable to beneficial microbes and more prone to contamination. By providing a consistent supply of fresh, oxygen-rich air, mycelial colonization and sporulation are optimized, reducing the risk of contamination and yielding a higher quality crop.
Depending on the species and cultivation method, different mushroom strains have varying FAE needs. Some, such as Lion’s Mane, prefer a high-humidity environment. In these cases, it’s important to use a humidity tent in order to cater to this preference. However, this can increase the cost of your kit, and it is possible that temperatures in your fruiting room may rise above the optimum temperature for the strain. If this occurs, the substrate will begin to cook the mycelium, causing it to fail and potentially ruining your harvest.
For this reason, it’s best to opt for an automated FAE system in your grow tent. Not only does an automated system help ensure that your mushrooms receive the proper amount of air, it is also able to control other environmental conditions like temperature and humidity. Using an automated system can save you time and effort, as it eliminates the need to manually attend to your monotub multiple times throughout the day. In addition, automated systems can provide consistency and precision that might not be achievable through manual methods.
Reduced CO2 Concentrations
As fungi, mushrooms require oxygen for respiration and produce carbon dioxide as a byproduct. Mushrooms need a balance of oxygen and CO2 to thrive, but high levels of one can stifle growth and inhibit fruiting. Without proper air exchange, mycelial networks can become stressed and prone to disease or contamination. With adequate FAE, the mycelial network can receive the oxygen it needs to grow and develop, while excess CO2 is expelled through ventilation.
During the initial colonization phase of mushroom cultivation, mycelial networks require higher concentrations of CO2 and lower concentrations of oxygen for optimal health. After mycelial colonization, the fungus transitions into the fruiting phase. During this time, mycelial networks need more oxygen and less CO2. Without sufficient FAE, high levels of CO2 can restrict mushroom development, leading to elongated stems or small caps.
The ideal level of CO2 in the environment for mushroom cultivation is 1,200-1,500 ppm. This matches the level of CO2 found in decomposing organic matter, the natural habitat of mushrooms. Without adequate air exchange, the CO2 concentration in a grow room can rise to such an extent that it cooks the mycelial network. This will lead to the formation of elongated stems and short cap sizes, known as “legging.”
As you can see, a lack of proper FAE negatively impacts all aspects of mushroom growth. Fortunately, there are a variety of methods for achieving a healthy and productive mushroom microenvironment through regular fresh air exchange. Some growers use manual methods, such as introducing air through the lid of the monotub, while others use more advanced systems that can automatically regulate airflow and provide FAE at specific intervals throughout the day. The frequency of these air changes depends on the specific strain of mushroom and other environmental factors. For best results, try to achieve consistent airflow to the mushroom monotubs as much as possible to maximize growth and reduce contamination. This will also help ensure that the mycelium and fruiting bodies develop to their fullest potential.
Prevents Contamination
As mushrooms grow and develop, they need to consume fresh air to respire and exhale carbon dioxide. The substrate they grow on also needs oxygen to metabolize and to trigger their fruiting instinct. However, too much CO2 can hinder this process, resulting in poor growth or even fruit death. FAE keeps CO2 concentrations low, allowing your mushrooms to thrive.
A growing room with a good ventilation system is essential for mushroom cultivation, as it helps to prevent contamination and other problems that can occur in stagnant conditions. This is why a fan-powered HEPA filtered flow hood is a vital piece of equipment for commercial or home mushroom growers.
In addition to maintaining a good environment, cultivators should be on the lookout for signs of contamination in their workspaces. This includes any odors, visible molds, or signs of improper sterilization techniques. If you notice any of these symptoms, it is important to practice a rigorous cleaning regimen, including washing hands, using a face mask, and disinfecting all equipment and surfaces that will come into contact with the substrate or mycelium.
While contamination can occur naturally in any growing space, preventing it is possible with strict steroid technique (known as “tek”) and adequate preparation and sterilization. This involves storing spores in an appropriate medium, growing a colony on a clean substrate, and sterilizing all equipment and surfaces before introducing a new medium or spawn.
During the colonization stage, it is important to make sure that your substrate has reached field capacity—the maximum amount of water it can hold against the force of gravity. This will ensure that your mushrooms receive all the nutrition they need without overdoing it, which can damage the mycelium and inhibit spore germination.
In order to reach field capacity, your mushroom spawn should be well hydrated and covered in a layer of mycorrhizal roots. Depending on the type of mushroom you’re growing, it may take several weeks to achieve this level of moisture. However, you can speed up the colonization process by hydrating your spawn with an autoclave or by using a humidifier.
Increased Yields
Much like any living organism, mushrooms require a precise environment to thrive and flourish. This includes temperature stability, high humidity levels once mushrooms begin fruiting, and adequate airflow to facilitate the fungi’s oxygen consumption and CO2 production. This last element is especially critical, because as mycelial networks shift from colonization to fruiting, their oxygen requirements increase significantly. This is why it’s important for cultivators to understand the importance of fresh air exchange, also known as FAE.
Insufficient FAE can suffocate mushroom colonies, inhibiting mycelial growth and reducing yields. A lack of oxygen also contributes to long, leggy stems and small caps – physical deformities that are a result of mycelium stretching to reach oxygen in stale, CO2-rich environments.
Luckily, there are plenty of effective ways to maintain adequate FAE in monotubs. The most basic technique involves misting the substrate with water 1-2 times per day (using 10-20ml of water each time). This allows the mycelium to absorb moisture while allowing the mushrooms to breathe and not become too damp.
Another simple way to improve FAE is by using a drill and a 1/2” bit to create holes around the sides of a bucket, creating spaces for airflow while still maintaining the integrity of the grow space. While this is not as effective as simply misting the surface of the substrate, it does provide an additional source of oxygen and helps reduce contamination.
Other methods include using a fan to blow air across the substrate, which increases mycelial growth and oxygen levels as well as removing carbon dioxide. This is ideal for those who don’t have the time to manually attend to their monotubs multiple times a day.
A great way to improve yields even further is by utilizing multiple 5-gallon buckets for a single mushroom kit, ensuring that the entire colony is exposed to fresh air as it grows and fruits. Many home growers choose to use this method because it is a cost-effective way to get the most out of a single kit. It’s worth mentioning, however, that this method can be a little tricky to manage because it requires regular maintenance and frequent attention in order to keep the mycelium and substrate clean.
