How do they grow mushrooms? (2024)

The process of growing mushrooms is a mystery to most people. Although there are a few “how to grow mushrooms” tutorials around, many of them skip out on a lot of steps and make it seem way easier than it actually is. (Add “seeds” to straw and poof! Mushrooms!)

This leaves a lot of people in the dark. Admittedly, mushroom cultivation is quite different from growing garden plants; but the process can be simplified all the same.

There’s no way a complete guide to growing mushrooms could be described in one single post, but I hope to provide a basic outline for people who want to learn more.

So – although there is an endless array of specific cultivation techniques in use around the world, growing most mushrooms generally consists of the same7 steps.

This involves placing mushroom spores or a viable tissue sample of mushroom on a nutrient rich media. This needs to be done in anextremely clean environmentso that bacteria and molds don’t land on your petri dish and out-compete the mushroom culture.

STEP 2: Transferring the mushroom culture (known as mycelium) onto sterilized grain

Again, in an extremely clean environment, cut a sample of mycelium and transfer it into a jar ofsterilized grain. The mushroom mycelium will start to grow out, running across and devouring the grain, eventually taking over the whole jar.

STEP 3: Expanding the grain jar exponentially to create grain spawn

Bits of grain, now called spawn, can be used to inoculate numerous other sterilized grain jars, exponentially increasing the volume of available spawn. One jar can typically be used to spawn ten more jars of similar size.

STEP 4: Spawning the grain into a suitable substrate and fruiting container

Once you have a satisfactory amount of grain spawn, it can be used to inoculate a substrate on which the mushrooms will eventually grow. The type of substrate used is dependent on the species of mushroom you are growing.

Typical substrates include straw, wood chips, or compost. Depending on the type of substrate used, it will also have to be pasteurized or sterilized prior to inoculation.

STEP 5: Allowing the mycelium to overtake the substrate

Once the substrate is inoculated, the mushroom mycelium will continue running, consuming nutrients and engulfing the substrate. Once the entire substrate is engulfed in mycelium, you can attempt to induce pinning.

STEP 6: Inducing pinning of the mycelium by altering the environmental conditions

When the environmental conditions are suddenly changed, usually by dropping the temperature and increasing the humidity, the mycelium will start to form little knots which eventually turn into pins. Check outthis articleto learn about the mushroom fruiting environment.

STEP 7: Allowing the mushrooms to fruit. Harvest your mushrooms in subsequent flushes

Finally, many of these pins -if given the right conditions- will continue to grow, drawing up water and nutrients from the substrate and rapidly turning into full sized mushrooms. If a proper environment is maintained, a healthy substrate can produce numerous “flushes” of mushrooms, allowing the cultivator to harvest the mushrooms 2 or 3 times.

One incredible aspect of mushroom cultivation is the ability of the mushroom mycelium to grow out exponentially, achieving mass thousands of times its original size. For example, a fingernail size slice of culture from a petri dish will grow out to fill a quart size grain jar. That grain jar, in turn, can be used to spawn ten more jars. Those jars can be used to spawn another 100 grain jars, which in turn can be used to spawn 1000 jars!

Eventually, the mycelium will lose vigor and become exhausted, but it is nonetheless incredible that a tiny piece of mycelium can go on to produce thousands of pounds of mushrooms.

This is in no way a comprehensive guide to learn how to grow mushrooms – but simply a basic outline of the process. I plan to write more about these steps and many other mushroom topics, with great articles appearinghereon our blog.

In the meantime, interested readers should consult the book“Growing Gourmet and Medicinal Mushrooms” by Paul Stamets.This book provides an incredible overview of mushroom cultivation, and is a must read for anyone interested in growing mushrooms.