If you are thinking of having mushrooms at home, then you may have researched mushroom grow bags before. However, there are some important things you need to know before you immerse yourself in the world of cultivating mushrooms.
What is a mushroom grow bag?
When people refer to a mushroom bag, they are referring to a gusseted bag or one that is folded with the sides facing inward. This is done so that the bag folds small and can lay flat. But it also opens wide enough to allow for a large amount of grain or sawdust. This bag allows for sterilization as well. This allows the cultivator to fill between the gussets, which prevent contamination from the air.
Other mushroom grow bags may also be referred to as autoclavable. This means that they can stand the high temperature of autoclave, also called sterilizer. This process is usually done in a pressure canner, at about 250 degrees F. It can sometimes last many hours at once.
You may also hear the term polypropylene. This is just a material that the bag is usually made of. This material doesn’t melt unless the temperature surpasses 270 degrees F. Bags made with this material are great for holding grain or sawdust during sterilization.
Finally, if you hear the term filter patch, this is just a comment on the filter that is on the front of the bag. This filter allows for mushroom cultures in the bag to get fresh air. But it won’t get contaminated by things like bacteria or mold. This filter is essential because without fresh air, the cultures can’t grow. But if the bag is open entirely, the mushrooms could get contaminated.
Here are the 5 things to know about mushroom grow bags:
Fact #1: Using a spawn bag makes it easier to spread the spawn
While some people prefer to use mason jars in creating the first generation grain spawn or run a trial, these jars are not ideal for producing large volumes of spawn. Using a spawn bag allows for the spawn to be broken up easily, which helps you mix it and also speeds up colonization.
A spawn bag is also a great way to spread the spawn to create a substrate. You can get up to 5lb or more of spawn in a large spawn bag, and this is enough to have a small log or many blocks grow mushrooms.
Fact #2: Make sure to use filter patch grow bags for fruiting blocks
Using filter mushroom grow bags is necessary for making sawdust fruiting blocks. One bag will result in about 5lb of fruiting block. However, using this type of bag allows you to mix the spawn after inoculation. The filter patch will then promote growth, while the culture expands through the sawdust.
When the mushrooms are colonized completely, cut the top and allow them to fruit.
Fact #3: Some people use the bag as a way to promote fruiting
In some cases, you can promote fruiting by using the bag as a humid chamber that gets the mushrooms to fruit. In this case, there is not much fresh air in the bag, so you should open the top to allow for fresh air exchange. Don’t open it too early, though, or you may ruin colonization because of contamination.
Keep in mind too, that some mushrooms grow very differently, so you should do some research to see what to expect.
Fact #4: You can reuse your grow bag
If you are making fruiting blocks or spawn bags, you may want to use brand new mushroom grow bags. However, you can reuse your bags for other things. Some spawn bags can be used to pasteurize the casing layer and you can set it in a pot of hot water on the stove. It may rise to the top, so consider using something heavy to hold it down.
You can also use these bags to make straw logs, in which they can replace the tubing. Simply fill the clean bag with pasteurized straw and grain spawn, which is just what you would do when growing mushrooms on straw.
Fact #5: The filter size matters
If you are new to buying mushroom grow bags, you should always take a close look at the filter. You can find the filter size on the bag denominated with a micron rating, which is just a way to describe the pore size. Sizes range from 0.2 to 5 micron.
When you use the bags for fruiting blocks or spawn bags, choose a small micron, as this protects the substrate from contaminants. A bigger size allows for more air exchange, so it can easily lead to contamination.
Time to find your grow bag!
You now know all about mushroom grow bags, from how big to what material they are made of, so you can’t make a bad choice. Make sure to always read the materials list and any special instructions.