FAQs About the Uses of Mushroom Grow Bags and More

Learn More About How We Deliver Excellence for the Mushroom Industry

Whether you’re an individual grower or operating on an industrial scale, Unicorn Bags is committed to delivering our customers with the quality, service, and innovation that has defined our breathable grow bags for over 30 years.

We also distinguish ourselves in the mushroom industry by providing educational resources to help you make an informed decision about the products and approaches you should use to experience the many uses and benefits of mushrooms and other fungi.

Key Information on Mushroom Cultivation Bags, Growing Specific Mushroom Types, and More

A filtered grow bag is a polypropylene or polyethylene bag that is used for spawning mushrooms. Growers begin with substrate (organic materials that offer an ideal environment for mushroom growth), which they place inside the bag.

A quality bag essentially creates optimal environmental conditions to produce a large volume of mushrooms. The filter on the side of the bag is for gas exchange. Mushrooms produce a great deal of carbon dioxide (CO2), while also requiring oxygen from outside of the bag.

While there are alternatives for cultivating mushrooms (they do, of course, grow on their own outdoors), filtered grow bags control the yield and quality of the mushrooms you grow, while also preventing contamination. A highly effective, high-quality bag will deliver yield, quality, and safety with the greatest rate of consistency. Healthy mushroom growth will allow you to experience the uses and benefits of mushrooms.

Our mission is to provide the highest quality, cost-effective bags in the global mushroom industry.

Unicorn Bags’ grow bags are:

  • Manufactured in the U.S.A.
  • The most trusted technology for a wide variety of individual and industry uses
  • Optimized for high performance
  • Designed from our own resin to produce durable, high-temperature-withstanding plastic
  • Built, shipped, and delivered with a commitment to extraordinary customer service

The substrate used for spawning mushrooms needs to be sterilized to ensure fungi can grow in a contaminant-free environment. An autoclavable bag is a grow bag that can be sterilized in an autoclave, which is an industrial steam-sterilizing machine that kills contaminants, like bacteria. Unicorn Bags are designed with optimized materials for sterilization to ensure the best possible growth conditions, so growers can use mushrooms and fungi for their specific needs.

Unicorn Bags are used in the agricultural, culinary, medical, and biocontrol industries, among several others. As the uses and benefits of mushrooms continue to expand, Unicorn Bags has continued its growth to meet demand for superior controlled growing environments.

Unicorn Bags can grow many kinds of fungi and mushrooms that require a controlled environment for high-yield, high-quality growth. Unicorn Bags can grow highly popular edible mushroom species including oyster, shiitake, and portobello mushrooms.

1. Mushroom Production Bags:
Generally used for production of shiitake and other species that require steam sterilization, these bags are side gusseted:

  • Polypropylene 12.8 in. wide x 19 in. long
    • Effective filter size: 1 and 5/8 sq. in. 
      • Type 14 – 0.5 microns
      • Type 14A – 0.5 microns
      • Type 3B – 5 microns (can be sealed before autoclaving)
      • Type 3T – 0.2 microns
    • Polypropylene 15 in. wide X 21 or 25 in. long (Type XLS) 
      • Effective filter size: 2 x 3 in.
    • 9 in. wide X 18 in. long (Type 10)
      • Filter types A, T, and B, with injector port.
    • 7 in. wide x 18 in. long (Type 4)
      • Filter types A,T, and B, with or without injector port.
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In addition to the above sizes, we can produce many custom sizes. Custom polypropylene bags can be gamma ray sterilized. Polyethylene and HDPE bags with filters are also available.

2. Biocontrol Bags
These bags use polypropylene and polyethylene materials. They are suitable for steam sterilization and gamma ray irradiation:

    • Lab use: 7 in. x 9 in. with two 1 and 5/8 in. x 3 in. filters
    • Large scale production: 15 in. x 25 in. single or double layer with high vent B filter 3 x 15 in. 
    • Many custom sizes are also available.

Unicorn Bags are manufactured from heat-sealable polypropylene plastic. Unicorn Bags include the following characteristics, making them the superior choice for grow bags:

  • Polypropylene resists sterilization temperatures. 
  • Polypropylene is highly cost effective.
  • Unicorn Bags’ polypropylene is made from virgin resin. 
  • Our bags are tested with several fungi strains for optimal growth characteristics.
  • Our resin blend has an antibacterial effect.
  • The entire manufacturing process from quality control to packaging is operated by Unicorn Bags.
  • Unicorn Bags also has polyethylene bags available for customers.

The photos and descriptions below illustrate the types of filters that can be incorporated into Unicorn Bags:

Our Type B filter has high gas exchange characteristics. With 90% pore coverage, the pore sizes are larger than the A filter, at 5 microns. Due to these characteristics, B-filtered bags can be sealed before autoclaving. For most other bags, either the filters allow competing fungi to enter, or too-small pores will pop during autoclaving.

Our T filter has 0.2-micron pores. They are 90% efficient and are designed for spawn production.

Our Type A filter is designed for shiitake cultivation. It has a nominal 0.5-micron pore size, meaning 80% efficiency at approximately 0.5 microns. This filter was also designed to have a surface area of 50% for breathability. This allows shiitake mycelium to grow in a higher CO2 environment.

Unicorn Bags’ cultivation resources for a wealth of information about growing mushrooms and other fungi. 

We also recommend the U.S. Mushroom Council, as well as The Mushroom Growers’ Newsletter, a 32-year labor of love with more than 350 issues. 

Follow us on social media for helpful tips and updates on mushroom benefits and uses. Facebook Instagram TikTok

Visit Unicorn Bags customer service for information related to payments, as well as shipping and returns. Our customer service resources also include customer service FAQs related to buying from Unicorn Bags. 


Feel free to send us a message online at any time. You can also call us at (469) 298-3558. We are located in Plano, Texas.

Shop the Full Unicorn Bags Inventory

Order directly from our online shop to get products from Unicorn Bags, the globally recognized manufacturer of grow bags for the mushroom industry.

The Unicorn Bags shop offers a quick, easy way to select the bags and other products you require for superior cultivation.

Need help with an order? Do you have further questions about our bags? Visit Customer Service, and we’ll be happy to assist you. You can also contact us online or by phone.