Experts Caution Against Growing Non-Native Fungi at Home Due to Ecological Risks

As at-home mushroom cultivation gains momentum, UK experts are raising red flags about its potential impact on biodiversity. Growing non-native fungi could have profound effects on local ecosystems and threaten native species. 

Understanding the ecological risks

While mushroom growing can be a fun and exciting activity, non-native species planted in gardens or disposed of in compost could have major environmental implications. Once fungi establish themselves in an area, they are difficult to remove since their tiny spores can spread for miles.

As we’ve seen with non-native garden plants, there are concerns that non-native mushrooms could replicate the invasive behavior of other previously popular garden plants like Japanese knotweed, rhododendron, and bamboo. Sheila Das, a garden manager at Chelsea’s RHS Wisley, is worried that non-native fungi could change the microbiology of soil and become nearly impossible to remove.

“We are still learning much about the world of fungi, so introducing alien spawn into your garden by accident (ie species not native to this country) could potentially unlock many issues just as we have learned from the past with invasive plants and imported plant diseases,” she said. “Alien fungi could potentially be even harder to control than alien plant species as their manner of growth is so complex and they can spread throughout soil and other organisms very quickly.

If a non-native species of fungi makes its way out of the garden and into the environment, they could outcompete native species for resources. When non-native species flourish in an ecosystem, they can cause a decline in native fungi and flora, reducing biodiversity and threatening the overall health and balance of the area taken over. 

The introduction of non-native fungi can also disrupt the soil’s chemistry and microbiology by altering the balance of microbial communities. If this balance becomes dysregulated, there could be significant issues for the health of plants and the overall ecosystem.

Furthermore, if a non-native and native fungus happens to crossbreed, the genetic integrity of the native species would be compromised. Ultimately, genetic pollution could lead to the loss of certain genetic traits that are crucial for the survival and adaptability of native fungi. This hybridization could produce fungi that do not function as effectively as their native counterparts, further disrupting the ecosystem.

“There are a lot of gaps in our knowledge about introducing mushroom spawn from different countries. Research has found different populations across the world have some genetic variation, and we are not sure what impact introducing a different population will have on the UK populations,” said RHS plant pathologist, Dr. Ruth Chitty.

“There is a possibility that the introduction of species from other countries will have negative effects, such as outcompeting native species. There are mushroom growing kits for sale that contain UK collected spawn, which reduces the risk to UK fungal populations.”

Best practices for sustainable mushroom cultivation

For those who love growing mushrooms but want to mitigate the ecological risks, here are some of the best practices to follow:

1. Choose native species

Native species that are adapted to the local region are less likely to cause any ecological disruption. Try to avoid exotic species that could potentially become invasive.

2. Properly dispose of spent mushroom substrate

Although composting keeps waste out of landfills, it’s important to ensure spent mushroom substrates are disposed of in controlled environments.“If you crumble up the grow kit after it stops producing for you, it would likely be taken over by the molds and bacteria in the compost itself,” suggests Dr. Greg Thorn of Western University in London, Ontario. 

3. Monitor and manage mushroom growth

If you are already growing non-native mushroom species, try to monitor it regularly to detect any early signs of it spreading. Additionally, do your best to harvest the mushrooms before they begin releasing spores to prevent uncontrolled spread.

Growing responsibly

This issue is not limited to the UK. Last year, scientists recognized the growing threat of non-native golden oyster mushrooms taking over woodlands throughout North America. Its spread was attributed to the rise of at-home mushroom growing. However, at the rate golden oysters have been spreading, it’s likely that the fungus has established itself as a permanent resident in U.S. forests. 

“You will never outrun a fungus ever. The fungus is going to win. We don’t even know what measures we are going to take to abate the quantity that’s out there. It’s either going to find balance or take over,” argues Tavis Lynch, chairman of the cultivation committee for the North American Mycological Association.

Nonetheless, as more people understand these ecological risks and move towards more sustainable practices, we may be able to prevent the spread of other non-native fungi species in the future. By understanding the risks involved with at-home mushroom cultivation, gardeners can continue to enjoy the benefits of mushroom growing while ensuring that local ecosystems remain a sanctuary for native species.