As you learn more about mushroom cultivation, something you’ll notice pretty quickly is that there’s a lot of talk about bags. It seems that mushroom cultivators use all kinds of different bags—and it’s true that there are different styles for different applications—but there are really only two different kinds of bags used in mycology: mushroom grow bags and mycelium spawning bags.

In today’s entry on our magic mushroom growing supplies blog, the team here at Monster Mushroom Company has decided to delve a little deeper into these bag types—what’s the difference between a mushroom grow bag and a spawning bag? How do they work and what are they used for? Do you have to have a spawning bag or a grow bag, or are there other ways to grow mushrooms?

All these questions and more will be answered. Feel free to use the links below to skip ahead to the section you’re most curious about:

Before we begin, let us take a moment to remind you that we offer readers like you a completely free mushroom growing eBook. This beginner-focused guide will give you all the information you need to start participating in the wonderful mushroom cultivation hobby—critically, it has a full glossary for commonly used mycology terms, so if you see anything in this blog post you don’t understand, make sure to use it as a reference!

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What’s the Difference Between a Mushroom Grow Bag and a Mushroom Spawning Bag?

Mushroom grow bags and mushroom spawning bags may look similar, but they serve very different purposes.

A mushroom grow bag is, as the name implies, used to actually grow mushrooms. If you’re familiar with the mushroom life cycle, you know that mushrooms are in fact the fruiting body of the much larger overall fungi, which primarily consists of mycelium—that spiderweb-like, root-like system which grows underground. Colonized mycelium is introduced to a grow bag alongside a nutrient-rich substrate.

As you may have already guessed from the above description, a mushroom spawning bag—which should really be called a mycelium spawning bag—is a bag designed for the propagation of mycelium. This is the step in the mushroom cultivation process that actually comes before one would use a mushroom grow bag.

In the following sections, we’ll describe how to use both types of bag, their benefits, and what alternatives you may also wish to explore.

How to Use a Mushroom Grow Bag

mushroom grow bag filter patch

Some mushroom cultivators like to use mushroom grow bags because this method of growing offers several benefits:

  • Mushroom grow bags are generally pretty easy to keep sterile, especially if they’re equipped with a filter patch (more on this in a moment)
  • Mushroom grow bags can help growers to conserve space
  • Since mushroom grow bags are almost always clear, it makes observation easy
  • The bag can be punctured, allowing mushrooms to sprout out from any direction rather than just up
  • Mushroom grow bags are extremely affordable in great quantities

Perhaps the most noteworthy benefit of a mushroom grow bag is the enhanced sterility of the environment inside the bag. If your bag comes with a micron filter patch, it will allow air to get inside without introducing unwanted bacteria or other contaminants.

To use a mushroom grow bag, simply add your colonized mycelium spawn—which you may have propegated using a spawning bag, described below—into the bag alongside your fruiting substrate of choice. There’s more to it than this, of course, such as temperature control, fresh air introduction, and hydration, but those are the basics of how to use a mushroom grow bag.

How to Use a Mushroom Spawning Bag

A mushroom spawning bag, or as we called it earlier, a mycelium spawning bag, is a special bag designed to allow the propagation of mycelium in a controlled, sterile environment (namely, inside the bag).

A good spawning bag will be sterile. It’s a good practice to always clean the bag before use with an alcohol solution. The bag will then be filled with your spawning substrate of choice and sealed. Clean the outside again before introducing spores to the substrate.

The best spawning bags will have self-healing injection ports. This allows you to use a mushroom spore syringe to puncture the port, inject the spores (a process called inoculation), and then remove the syringe. The injection port will close up on its own, minimizing the possibility of contaminants entering the spawning bag.

Once the spawning bag has been completely colonized by mycelium, it can be safely opened and introduced to a fruiting substrate. This is typically done in another bag, but nothing quite as specialized as a mushroom grow bag or a substrate bag—a simple garbage bag will do just fine. The colonized mycelium is broken up and mixed into the fruiting substrate. This mixture can then be placed into a mushroom grow bag or, as we’ll learn below, into a mushroom grow kit.

Mushroom Grow Bags vs. Mushroom Growing Kit

Many mushroom growers prefer the convenience and ease of a mushroom grow kit instead of using mushroom grow bags. In the kit we offer here at the Monster Mushroom Company, a monotub growing chamber is used instead of a mushroom grow bag. While it’s all ultimately a matter of preference, many growers find this method of mushroom growing to be easier and capable of producing very large, healthy harvests even if the grower is a total beginner.

However you choose to grow your mushrooms, remember to have fun! After all, mushroom cultivation is the greatest hobby in the world.