An organic mushroom is one grown utilizing cultivation practices that avoid the use of non-organic substrates or synthetic chemicals. In some cases, mushrooms may also be certified organic, meaning that they follow the regulatory framework set out by the USDA (or similar agencies in other countries) for organic production. Due to the challenges mushroom growers may face sourcing certified organic materials, the USDA does allow some flexibility in this regard as is outlined below.
It’s also important to note that while certification can benefit consumers purchasing mushrooms at a big-box store, not all growers who utilize organic practices have the certification. In fact, many small growers, like those you might meet at your local farmers' markets, probably have stricter guidelines than those set out by the USDA, despite not having a certificate. If there’s any doubt, it’s always fair to ask!
USDA Organic Mushroom Production Regulatory Framework
Below is a summary of the regulatory framework outlined by the USDA for the organic certification of mushrooms. This summary includes the new guidelines that took effect in February 2025. You can find technical details on the new regulatory framework here.
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Organic Spawn: The regulatory framework says that spawn must be organic certified if it is commercially available. Organic spawn is cultivated utilizing an organic-growing medium (such as organic Rye) and is free of prohibited substances. This means that if no equivalent organic spawn exists, and the grower can provide evidence of this, then they may utilize non-organic spawn.
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Organic Mushroom Substrates
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For compost-based substrates like those utilized for button mushroom cultivation, growers DO NOT need organic plant or animal materials for their compost feedstock. The only requirement is that the compost be processed at ≥131°F for at least 3 days to eliminate any harmful microorganisms.
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Uncomposted substrates, like those utilized for Oysters or Lion's Mane, must be organic unless they are commercially unavailable. Like for spawn, efforts to source organic alternatives must be documented.
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Wood materials (logs, sawdust, chips) do not need organic certification but they must not be treated with prohibited chemicals after harvest.
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Sanitation and Pest Management
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Some substances like hydrogen peroxide, peracetic acid, and sodium bicarbonate are allowed for sanitization. Prohibited substances include quaternary ammonium and others due to their persistence in the environment. You can find a list of permitted substances and prohibited substances here.
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Growers must prove that they are utilizing biological and cultural control methods and only utilizing approved synthetic substances when necessary. For more info, check out this article by Penn State about the Basic Integrated Pest Management Practices for Organic Mushroom Farms.
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Certification
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Growers must submit an organic systems plan (OSP) detailing their substrate composition, sourcing, and other relevant documentation. You can find an example of an Organic Systems Plan form provided by the New Hampshire Department of Agriculture here. To comply, growers must maintain detailed records of all of the materials utilized for the cultivation, as well as all of their sourcing efforts.
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Facilities must be open to yearly USDA-accredited inspections, where they can visit your farm and check for any compliance issues.
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Mushrooms that meet 100% of the requirements set out by the regulatory framework can utilize the USDA Organic seal. An additional label saying “Made With Organic Ingredients” can also be acquired if the substrates are made of 70% organic materials.
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As of 2019, the USDA also ruled that pre-inoculated grow bags must be produced in a certified organic facility.
Alternative Certifications
It’s relevant to note that there do exist some alternative certifications, such as the Certified Naturally Grown (CNG) certification, that outlines its own standards for mushroom cultivation. While the standards are relatively similar, CNG is stricter on its use of GMO materials and their water and environmental considerations. Another certification with more stringent standards is the Regenerative Organic Certified, which has already granted certification to some mushroom farms.
Conclusion
Organic certification gives consumers the assurance that the products they consume are produced to a set standard and with the absence of harmful chemicals. While the organic certification for mushrooms provides some flexibility, it does at least ensure good practices to a certain degree. As mentioned before, many small growers who don’t have the certification may still work with organic practices.
