‘Substrate’ is a fancy word for food; So you may have already figured out that mushroom substrate is food for the mushroom. Of course, there’s more to know…
Do you know what mushroom substrate is? Substrate is the material that mycelium consumes. We are putting the mycelium into the substrate, or into the mushroom’s food source, when we inoculate with whatever mushroom we want to grow. Our substrate is the food that the mycelium is going to consume and the mushrooms will fruit out of.
Mycelium becomes entwined with the substrate. It’s similar to making tea; You have your tea bag and water for making tea. When you combine the two, the tea and the water become one. It’s similar with mushrooms. When you inoculate by putting the mycelium in the substrate, the mycelium grows all throughout the substrate and cannot be separated. The two become one. The fungus cannot be separated from the substrate itself.
However, fruiting does take place. Mushrooms grow from the substrate and can be harvested from it.
Common mushroom substrate examples to know and grow with
A common mushroom substrate many beginning mushroom farmers use is grain. In the video below I show some examples of these substrates, including grain.
We’ve been using oats, and we add gypsum for micronutrients and calcium for the mycelium to grow effectively. These are the two substrates we mainly use when we are not trying to fruit mushrooms. When we are growing out mycelium and want fast growth.
The base substrate we use when fruiting mushrooms is sawdust. We get 15-30 yards at a time. It is all hardwood sawdust and the pile shown in the video is primarily oak. We get it all from a local mill.
The particles are relatively small and easily consumed by the mushroom mycelium.
Two commonly-added ingredients to sawdust as a mushroom substrate for fruiting
The first is wheat bran, which we add when growing shiitakes. It’s important to note that regarding mushrooms and gluten, all the gluten that is in wheat is broken down by the mycelium and that protein is no longer there.
The other is soybean hull, which is great for oysters, lion’s mane, and other species.
Preparing the mushroom substrate
We user a Pack one yard mixer. It’s a ribbon mixer, so when you pick up the hood and look inside, you can see the ribbon. When the mixer is on the ribbon moves around the substrate while also adding water. For about three years we hand-mixed the substrate ourselves — several thousands of pounds each week. Having this machine now allows for a much easier mixing process.
Button mushrooms and compost
Lastly, we’ll quickly mention button mushrooms. We do not grow these mushrooms because we mainly focus on choice edibles, but people who are growing button mushrooms often do it with compost as the mushroom substrate. The agaricus is primarily grown on compost with manure.
There you have some quick information on mushroom substrates!