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Conditions for Fruiting Mushrooms
When learning how fruiting mushrooms works, there are four main parameters to focus on which we will cover below. Even if you maximize all variables properly, mushroom growing can be unpredictable. However, you will most certainly need to pay attention to humidity, CO2 levels, temperature, and lighting in your fruiting chamber.
Humidity
Humidity is one of the key parameters when it comes to successfully fruiting your mushrooms. The ideal humidity for fruiting will be anywhere from 75% to 90%. In the initiation phase, which is commonly the first four days of fruiting, you will want the humidity to be higher, closer to 90% the better. When mushrooms enter a pinning phase, they start to be more resilient to lower humidity levels, therefore you can drop humidity down to 80% or even 75% without it having a huge impact on the fruiting process.
CO2
Most experts suggest that C02 levels during the fruiting phase shouldn’t exceed 1000 parts per million (ppm). The ideal CO2 levels should be in the range of 500 to 800 ppm. If the levels of CO2 concentration are higher than 1000 ppm during the fruiting phase, the yields will most likely decrease. However, there are some mushroom species that are more tolerant to high CO2 levels, like shiitake and lion’s mane. In addition, during the pinning stage monitoring carbon dioxide is crucial. Mushrooms that start to pin under high CO2 levels will extend the stems in order to find oxygen, this will result in mushrooms with long stems.
Temperature
The ideal temperature range for fruiting is between 55 and 75°F, which is slightly lower than the temperature during incubation. The sweet spot is somewhere around 60 to 65°F, at these temperatures mushrooms tend to grow the fastest. Mushrooms grown at lower temperatures grow slower but they are often meatier and of a higher quality.
Lighting
Mushrooms require quite a bit of light to grow well, contrary to popular belief. Light used for the fruiting chamber should be in the range of 5000k to 8000k, however, 6500k is considered the best spectrum for fruiting your mushrooms. There are a few of lighting schedules such as 12 hours on 12 hours off, or 16 hours on and 8 hours off. Although 16:8 is most commonly used since the mushrooms can get a bit stemmy if left in the dark for too long.
When is The Right Time to Start Fruiting Mushrooms?
The process of fruiting involves forcing the substrate to produce “fruit bodies”, commonly known as mushrooms. Once the substrate is fully colonized, it is ready for the next step, which is the fruiting stage.
The process of colonization will often take 20 to 30 days, depending on the environmental temperature. It’s important to identify what is healthy mycelium and what are potential contaminants. This process, in most cases, is relatively easy, as the mycelium is easily distinguished by white and stringy Hyphae. Once fully colonized, the substrate will require proper environmental triggers in order to form nice and big mushrooms.
After the mushroom grow bag has fully colonized, look for pin formations on the substrate. As soon as it’s exposed to fresh air, mushrooms will start to take form, as they need oxygen in order to grow.
How To Start Fruiting Mushrooms?
After your substrate has been colonized, you will need to decide how you want to fruit it. The substrate can be left in the bag to fruit or moved to an external container like a plastic tote, terrarium, or mono tub. Fruiting the substrate in a tote will most often result in larger yields, as the substrate will have more area to produce fruit bodies. However, this method requires additional steps and equipment and a clean and sterile growing environment. Therefore it’s not recommended for complete beginners to start here.
1. Fruiting Mushrooms in a Spawn Bag
This is one of the simplest methods of fruiting as the bag itself will serve you as a fruiting chamber. Once fully colonized you will want to cut open the bag in order to give the substrate some fresh air. If the substrate appears to be drying out you will want to mist it with some clean or distilled water. Fold the bag shut to hold in the moisture, this can be done with paper clips or a piece of clean tape.
To induce fruiting you will want to drop down your temperature, it’s usually around 70-75 degrees. However, not all mushroom species are the same, therefore you will want to check out what are the ideal temperatures for the mushroom species you are cultivating.
In order to take your substrate from a vegetative to a fruiting stage, temperature, oxygen level, and humidity should be ideal. Controlling all three factors at the right time will cause the substrate to start fruiting. Usually, it takes about 10 to 16 days for fruiting to start.
Once the substrate starts to fruit you will see tiny mushrooms form on top of the substrate. As the pins start to develop and grow you may need to open the bag to make more room for them to grow. Once fully grown harvest them and fold the top of the bag closed again. At this point, you may need to mist the substrate to rehydrate if necessary. In the following weeks, more fruits should continue to grow.
2. Fruiting Mushrooms In a Mono Tub or Terrarium
In order to use a mono tub or terrarium you should load bulk substrate and inoculate it. The amount of substrate and spawn you will use will depend on the size of your tub. You will want to have 3-5 inches of substrate.
Start by sprinkling about an inch of the bulk substrate into your sterilized tub. If it dried out during the pasteurization process, you will have to add some sterilized water to the blend as you are filling the tub. The next step is to add a thin layer of colonized grain spawn, after that add one more inch of the substrate and more spawn. Keep layering them up until you reach your desired depth.
It’s important to sterilize the tub and the lid with rubbing alcohol. Keep the tub in a warm place, out of direct sunlight until the mycelium fully colonizes the substrate.
When you start to see little pins or hyphae knots, you will want to case your tub. At this point, it’s perfectly safe to remove the lid from the bin.
You can case the tub with coco coir or vermiculite. A thin 1/2 to 1-inch casing should be equally spread over the whole tub and sprayed with water until its fully hydrated.
Keep the environment in the tub humid. Spraying it daily with water will keep the humidity at the correct levels. Also if you are not using a shotgun chamber you should likely place the lid slightly offset to allow more oxygen to flow into the tub. Light is also an important factor if you want your mushrooms to grow nice and healthy in the correct direction. Harvest the full-grown mushrooms, and repeat!
When Is The Right Time To Harvest Your Fruiting Mushrooms?
Harvesting mushrooms at the right time is depending upon the conditions in which they are growing in as well as the mushroom species you are cultivating. Size is not necessarily an indicator of when to pick the mushrooms, bigger doesn’t always mean better. A general rule of thumb is to begin harvesting when the caps start to turn from convex to concave – turning from down to up. Different fungi species will have different methods and times to harvest, here is when and how some of the most popularly grown mushrooms are harvested:
Oyster Mushrooms
Harvesting oyster mushrooms should occur 3 to 5 days after you see the first mushrooms begin to form. When you start to notice your oyster mushrooms beginning to turn upwards or flatten out, you should harvest before they start to drop their spores.
We have a complete guide on growing Oyster mushrooms here.
Button Mushrooms
When fully mature, the caps of the button mushrooms will pop open. That is the right time to start harvesting. Harvesting is usually done by cutting them with a sharp knife or just twisting them off the substrate. You can fill the empty space with more casing in order to make more space for new mushrooms. Most of the time they continue to produce mushrooms for 3 to 6 months after the first harvest.
Shiitake
Shiitake mushrooms grow on logs, as they are wood-loving species. Harvesting these mushrooms take time as it won’t take a place for at least 6 to 12 months. However, there are ways of growing them in sawdust blocks which can significantly speed up the process. After they start to cap, about three days later, they will be ready to harvest. Harvesting this species will take time, but with proper care, shiitake logs can produce mushrooms for up to 6 years, and possibly even longer.
Enoki
Enoki mushrooms are fruiting quite quickly, therefore it’s critical to observe them every day. Once they reach a suitable size, most of the time it’s between 4 to 6 inches, take a clean knife and cut the stems. If they’re set correctly you should be able to harvest multiple flushes.
We have a complete guide on Enoki mushrooms here.
The Bottom Line – Mushroom Fruiting
Check out this other article on fruiting mushrooms from Fungially.com here.
In order to successfully fruit your mushrooms humidity, temperature, CO2, and lighting should all be taken into consideration. Ideal humidity levels should be from 75-90%, with the temperature being around 60 to 65°F, as it’s considered a sweet spot. The concentration of CO2 should be no more than 1000 ppm. However, different species have different needs, so it’s important to be well-informed about the mushroom species that you are planning on growing.
The fruiting stage should be started after the substrate is fully colonized with the mycelium, there are many methods of fruiting with the most popular being:
- fruiting in mycobags
- fruiting in mono tub
- fruiting in tote, which is by far the method that will produce the best yields.
The right time to harvest can’t be exactly defined as it differs from species to species, although a general rule of thumb is to begin harvesting when the caps start to turn from down to up before they flatten out.
