Mushroom Grow Bags: A Comprehensive Guide

What are mushroom grow bags and where to find them.

5 min read - Feb 01, 2025

Oyster mushroom illustration

Over the years, mushroom cultivation has seen a surge in popularity. As more people join the foray, the resources and solutions to make the process easier have also increased. One of the essential resources for new and seasoned cultivators is mushroom grow bags. This article will explain what grow bags are and how to pick the right one for your next mushroom endeavor.

What are Mushroom Grow Bags?

If you're new to mushroom cultivation or want to experiment with growing mushrooms, grow bags will be an essential tool during your journey. Mushroom grow bags are heat-resistant plastic bags that contain a nutrient-rich substrate that your mushrooms will use to develop and grow. Their affordability and convenience have made them essential for home and commercial cultivators.

Mushroom Grow Bag Features

• Material: Usually made of polypropylene, these bags are heat-resistant. This durability is essential because grow bags must withstand the heat of autoclaving or steaming to sterilize the substrate.
• Injection Port: A self-healing injection port allows you to safely inject a spore or liquid culture without leaving an opening for competing bacteria or molds.
• Filter Patch: Each bag has a filter patch to allow gas exchange while providing a protective layer against outside contaminants.

Fruiting bag filter patch

Fruiting bag injection port

Spawn Bag vs. Fruiting Bag

Many people buy empty grow bags and then add and seal the substrate later. However, if you plan to purchase a grow bag with substrate already in it, you should determine if you need a spawn or fruiting bag.

Spawn Bag

The primary goal of spawn bags is to protect your substrate until the mycelium of your future mushrooms fully colonizes it. Once the bag is fully colonized, the contents are transferred to a fruiting substrate (possibly in a bag), where your mushrooms will fruit. Summed up, you shouldn't purchase a spawn bag if you aim to fruit mushrooms directly from it.

Fruiting Bag

Fruiting bags (aka all-in-one grow bags) are especially great for beginners because they allow for inoculation, colonization, and fruiting, all of which happen in one bag. Sticking with one bag reduces the space needed at home and significantly lowers the chances of contamination. Fruiting bags can achieve this by containing a mixture of grain for colonization and pasteurized materials for fruiting. If you want to get your feet wet with mushroom cultivation at home, we suggest going this route.

Shiitake mushroom fruiting block

Shiitake mushroom fruiting block

The Cultivation Process with Mushroom Grow Bags

Now that you know what grow bags are and their differences, let's take a high-level look at the cultivation process when using these bags. There are plenty of different routes you could take when using grow bags, but we'll assume a couple of points to keep things simple:

• You're starting with a grow bag with substrate already in it.
• You're planning to fruit directly from a grow bag.
• You have the materials needed to sterilize your grow bag (if you plan to use a spawn bag before transferring its contents to a fruiting substrate).

The General Process

Regardless of the mushroom you're trying to grow, the process from inoculation to fruiting is the same when using a fruiting bag.

1. Inoculation: Using a spore syringe or a liquid culture syringe, inject its contents into the mushroom grow bag via its self-healing injection point. The amount you inject will depend on the bag size, but the company that sold you the grow bag should provide this information.
2. Storage: After inoculating the bag, it should be stored in a warm, dark area of your home that doesn't get much traffic. The exact optimum temperature will depend on the specific mushroom you're trying to grow. A closet or cabinet are both great options.
3. Break and Shake: Once the mycelium has colonized 30-50% of your bag, it's generally a good idea to break and shake it. Break and shaking spreads the colonized grains throughout the bag, speeding up the colonization time.
4. Transfer Contents (if you're using a spawn bag): If you're using a spawn bag and it's fully colonized, you will need to open the bag and transfer the substrate to another bag containing a pasteurized fruiting substrate. After sealing the bag, it will also need time for colonization.
5. Induce Fruiting: Once the bag is fully colonized, it's time to cut it open to induce the fruiting process! Depending on the mushroom species, you'll either have to cut the top of the bag open or cut slits on the side of the bag. The storage location should also be cool and humid. However, the exact numbers also depend on the species, so research before this step begins.
6. Pinning & Fruiting: After misting and keeping your grow bag comfortable for some time, you'll first notice small primordia forming, also known as pinning. This pinning signifies that your mushrooms are on the horizon! However, to avoid aborts, it's still important to keep the environment optimal until the mushrooms grow to full size.
7. Harvest: Once your mushrooms have reached their full size, you can harvest them and reap the benefits of your hard work! You should also know that grow bags can usually give you two to three flushes of mushrooms. So don't get hasty and throw that bag away immediately!

Where to Purchase Your Next Mushroom Grow Bag

Oyster mushroom grow bag

Now that we've provided the essential details explaining grow bags, let's look at some of our favorite suppliers.

Midwest Grow Kits

Midwest Grow Kits is a small family-owned business with a proven track record in the industry. Supporting commercial and home growers alike, Midwest Grow Kits can provide everything you need to get started.

The Original Rye Spawn Bag

Premium 5 Grain Spawn Bags

North Spore

Launched in 2014, North Spore has quickly become one of the industry's best and most reliable businesses. With a robust catalog of products to support growers at all levels, you can be sure to find what you're looking for.

4 Pack Shroomtek Mushroom All In One Grow Bag

Shroomtek All In One Mushroom Grow Bag

MushroomSupplies.com

Based in Westminster, California, MushroomSupplies.com's 35,000-square-foot facility supports a growing team of mycologists with over 25 years of experience. Visit their site to view their vast array of mushroom supplies for any part of the cultivation process.

Mushroom Growing Kit - The Mushroom Grow Kit In-a-Bag™

Substrate for Dung-Loving Mushrooms

Conclusion

With this comprehensive guide, you now have the information to start your journey using a mushroom grow bag. Nothing excites us more than seeing others succeed in their mushroom endeavors. Feel free to follow one of our social media pages and share your progress. Thank you for reading, and best of luck from the mycoro team!