What is a Fruiting Substrate for Mushroom Cultivation?

People have been cultivating mushrooms for a very long time—perhaps tens of thousands of years.

Needless to say, the ancient practice of growing mushrooms has been around for a while. During such a long span of time, it’s natural that people have developed all kinds of skills, knowledge, and, of course, terminology based around the subject.

When you get really into fungi, that’s a good thing. More descriptors allow you to be more specific about what you’re saying or describing. Without all the terms that get thrown around like spores, inoculate, or spawn, we wouldn’t be able to communicate with one another as effectively. (And that’s not even counting all the crazy slang terms and “Teks”, or Technical Educational Knowledge, that people have come up with over the years.)

Ultimately, this is all a good thing. However, it can be daunting—to say the least—as a beginner. What does it all mean? Where do I start?

And it doesn’t help that sometimes terms get used interchangeably, have different meanings in different contexts, and otherwise suffer from some kind of inscrutable vagueness (at least to a beginner).

In today’s post, we’re going to clear up one of those terms in great detail, and that’s because it’s a really, really important one to understand: substrate. Specifically, fruiting substrate. By the time you’re done reading, you’ll know exactly what this substance is, why it’s so important, and where to get your own. (Spoiler: of course we have it in the Monster Mushroom Company shop!).

Before we get started, we’d like to quickly direct your attention to our free eBook, The Monster Mushroom Company Fungi Crash Course. A big part of the book is a “Mushroom Glossary” that briefly explains terms you might not understand yet—it’s well worth keeping a copy around for reference (and why not? It’s free!).

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All right, now that we’ve covered all our bases, let’s dig in. What’s a fruiting substrate anyway?

What is a Fruiting Substrate?

The term “substrate” gets used really often in the world of mushroom cultivation, so get used to seeing it!

As you’ll learn in a bit, there’s more than one kind of substrate. For now, let’s focus on what a fruiting substrate is.

Fruiting substrate refers to the medium that your mushrooms will grow in. In the simplest terms possible, it’s basically “just” soil—except that’s not entirely accurate, and any mushroom grower worth his or her salt will scoff at you if you tell them that their fruiting substrate is “just dirt.”

That’s because in order to be effective, the fruiting substrate needs to have a lot of different things. It’s not just the kind of stuff that you could dig up in your back yard. The best mushroom fruiting substrates are specially balanced blends. Skilled mushroom growers have likely spent quite a lot of time figuring out just the right pH levels, moisturizing agents, and other additives like vermiculite or gypsum.

In fact, those are all ingredients we use in our own fruiting substrate, our expertly-blended Super Shroom Final Fruiting Substrate.

In just a little bit, we’ll tell you why we picked the ingredients we did for our industry leading substrate blend. First, since you know what a fruiting substrate is now, let’s take a moment to look at when it gets used in the mushroom cultivation process.

At What Stage in the Mushroom Cultivation Process Does a Grower Use Fruiting Substrate?

Novice mushroom growers are often surprised to find out that the fruiting substrate isn’t actually used right away in mushroom cultivation. At least not if you’re propagating your own mycelium—the mycelial network first needs to grow into the spawning substrate (see, there’s more than one kind of substrate—more on spawning substrate later).

While we recommend checking out our video cultivation guide, or our written cultivation guide if you prefer, which will give you a much more comprehensive understanding of the cultivation process, here’s a brief rundown of how a typical mushroom grower would cultivate their fungi, from top to bottom:

  • Inoculate spawning substrate with spores
  • Allow mycelium to fully colonize the spawning substrates
  • Prepare a spawning chamber (i.e., a monotub)
  • Break up the colonized spawning substrate and mix it with fruiting substrates
  • Place the mixture into the spawning chamber
  • Tend to the needs of the fungi as it grows (temperature, moisture, light, and so on)
  • Wait a while!
  • Harvest fruiting bodies, A.K.A., mushrooms.

Once again, that’s a very condensed example of the general process. (Reminder: if you didn’t understand something, go grab our free eBook for its excellent glossary of terms and other information.)

Anyway, as you can see, the fruiting substrate wasn’t introduced until later on in the process. In fac, the mushroom cultivator is likely to start with a spawning substrate, which is absolutely critical—rarely (if ever) is it a good idea to attempt to get your spores/mycelium to colonize the fruiting substrate itself.

We’ll examine what a spawning substrate is in more detail shortly. For now, let’s take a moment to finalize our understanding of fruiting substrates and take a look at what goes into an effective blend.

What Goes Into a Good Fruiting Substrate?

As mentioned earlier, a good fruiting substrate isn’t simple dirt. While it’s possible that you could gather soil from your local area and grow mushrooms in it, you would likely get less-than-ideal results. Mushroom cultivators are often growing mushrooms for culinary or ornamental purposes, and thus always want to get the biggest, best flush they possibly can—and if possible, repeated flushes, which just isn’t that likely to happen with regular soil.

Whether you’re trying to cultivate mushrooms or azaleas, understanding the needs of the organism you’re attempting to grow is paramount. We believe we’ve developed the ideal environment for fungi with our fruiting substrate, but every cultivator has his or her own preferences, preferred mushroom varieties, growing environment, and so on.

So what, other than great soil, do you need in a fruiting substrate? In our Super Shroom Final Fruiting Substrate, we use some of the following:

pH stabilizers: pH (potential of hydrogen) is how chemists measure the level of acidity in an environment. Some degree of acidity is important and desirable by fungi (and many plants for that matter), but too much and you’ll have a failed crop. pH stabilizers are designed to do exactly what their name implies: keep the level of acidity just right throughout the entire grow.

Coco: Not to be confused with cocoa (as in hot cocoa), coco is a term you’ll see in both fungi and plant cultivation and actually refers to coconuts. Not coconuts entirely, but rather the fiber-like “hairs” found on the interior. This substance is called coco coir, or sometimes coco peat. It is an all-nature, organic substance that happens to be fantastic for mushroom cultivation. The little fibers not only provide nutrition, but also help to aerate the rest of the fruiting substrate, giving mycelium room to breathe (literally—mushrooms need air like humans do, not carbon dioxide like plants) and grow.

Vermiculite: This is a mineral—technically a hydrated laminar mineral—and it serves several important functions in a fruiting substrate. Perhaps the most important of which is that vermiculite is capable of improving moisture retention in the substrate and, as you likely already know, fungi love high levels of moisture. Vermiculite can also help to aerate soil, which as you’ll see with gypsum below, is extremely important for mushrooms to thrive.

Gypsum: Gypsum is yet another mineral and what’s called a “soil conditioner.” It’s a blend of calcium and sulfate, both of which offer many benefits to fungi. Calcium in particular helps as a balancing compound, allowing the mycelial mat to better consume other nutrients in the fruiting substrate (this is true in the plant world also; if you’ve ever seen a plant with a weak stem, it may have been due to not enough available calcium). Sulfate is the other critical component of this mineral, which helps mycelium further colonize the substrate by helping to break down any compacted soil.

Hydration: Water is, of course, of vital importance to all life, and mushrooms are no exception. We source our water locally, and that’s quite a good thing—Colorado is known for particularly great water in this part of the country. We hydrate our fruiting substrate with both distilled water and Rocky Mountain spring water.

Shitaki Mushrooms Growing Substrate Tips

Other than the ingredients themselves that make up the fruiting substrate, there’s one more absolutely essential component: the fruiting substrate must be sterilized. As you’ll quickly come to realize when working with mushroom cultivation, sterility is extremely important for not only your fruiting substrate, but your spawning substrate, tools, and general environment.

Sterility is so important because a young fungus is particularly vulnerable to bacteria and other microscopic organisms. While developing from the spore stage and into the mycelial stage this is especially true—many a novice mushroom cultivator who didn’t take sterility seriously has ended up with a failed grow.

Before we conclude our discussion about substrates, let’s quickly touch on spawning substrates and how they differ from fruiting substrates. Spawning substrates are different but equally as important as the fruiting substrate. As you may have already gathered, the spawning substrate is where your mycelium will originally grow.

It, of course, must also be sterile and is usually contained within a bag. Our spawning substrate is a grain-based spawn designed specifically to strengthen and hasten the colonization process. For more information, take a look at our Super Spawn Pack Of Sterilized Grain Spawn.

There’s More to Growing Mushrooms Than Just Substrate. You’re Also Going to Want…

This article has really only scratched the surface of what you’ll need in order to cultivate mushrooms. The good news is that the other components necessary—things like a monotub, a hygrometer, sterile handling equipment, and so on—are all relatively affordable and easy to source. Take a look at our article Everything You Need for Amateur Mycology at Home for more details.

If, however, you’d like to be absolutely sure you’re getting the best-of-the-best for your mushroom grow, you’ll definitely want to consider ordering our All-In-One Mushroom Grow Kit.

Monster Mushrooms Basic Grow Kit

Skip the Hard Work & Order a Time-Tested, Expertly Blended Fruiting Substrate for Your Next Mushroom Grow

Even if you don’t need an entire mushroom growing kit, we do still highly recommend you try out our Super Shroom Final Fruiting Substrate. We’re confident that once you cultivate a single harvest with this amazing and powerful substrate, you’ll want to use it again and again because the results are just that good.

Our fruiting substrate is available in a single 5lb bag or you can order up to 3 at a time. Alternatively, our All-In-One Mushroom Grow Kit comes with two bags of Super Shroom alongside everything else you could possibly need for a great mushroom growing experience, whether you’re a novice or an expert.

Further Reading & How to Learn More About The Monster Mushroom Company

We hope that you’ve found this article about mushroom fruiting substrate interesting and helpful. If you’d like to learn more about the equipment needed to grow mushrooms yourself, we’ll refer you once again to our comprehensive article Everything You Need for Amateur Mycology at Home.

We also invite you to see our video and written guides and, of course, we encourage you to shop at the Monster Mushroom Company store, where you’ll find everything you could possibly need to have a great harvest.


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