Mycorrhizae 101: How Fungi and Plant Symbiosis Can Help a Cannabis Grow Thrive

(Taynk/iStock)

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This article is sponsored by Hydrodynamics International.


As legislation around cannabis evolves throughout North America, backyard gardeners and professional farmers alike are growing more plants every year. This explosion of interest in cannabis cultivation has been accompanied by renewed attention about how to get the most out of cannabis crops large and small. Mycorrhizae supplements are among the tools now being put to work in both gardens and grow-ops. But what’s behind this symbiotic success story, and how does it help cannabis plants to thrive?

What Are Mycorrhizae?

Mycorrhizae are a class of fungi that thrive in symbiotic relationships with the root systems of plants. This partnership is common throughout the plant kingdom, and is often integral to the health of crops around the world. It may even have been key to the initial spread of plants on land—evidence suggests that mycorrhizal relationships date back more than 230 million years, to when plants were still working to make the transition from sea to land.

Mycorrhizae comprises many strains and species of fungus that thrive in symbiosis with plants
Morel mushrooms are the fruiting bodies of fungi in the genus Morchella, many species of which are mycorrhizae. (tomasztc/iStock)

Mycorrhizae may have made that transition more seamless because these fungi make life just a little easier for plants. For instance, mycorrhizae that pair with plants like cannabis penetrate the root, sharing in its nutrients. It’s in the fungi’s interest, then, to make sure the plant they’re partnered with is getting as many nutrients as it can—the better the plant does, the more healthy and successful its fungal partner will be.

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Benefits of Mycorrhizae

When mycorrhizae colonize a plant root, they proceed to branch out into the soil around it. “You can almost envision mycorrhizae as a series of secondary roots, coming off of the plant root,” says Jason Steinman, production manager at the plant nutrient supplier Hydrodynamics International. “Except those secondary roots are actually strands of fungus.”

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Those additional branches serve an important purpose, expanding the surface area and reach of a partner plant’s root system. More surface area means that the roots are in contact with more soil, more water, and more nutrients, so that they can make the most of the resources that surround them. The result is that plants colonized with mycorrhizal fungi have been found to be more resistant to factors like stress and drought.

mycorrhizae fungus help plant roots absorb nutrients and minerals from soil.
Mycorrhizae can supplement the root systems of plants from cannabis clones to tomato starts, making them more resistant to stress. (Phoenixns/iStock)

“If you have plants that are in a drought scenario, you will see leaves that are drooping or falling off, and you’ll eventually see the whole plant die,” says Steinman. “In plants treated with mycorrhizae, you’ll see that much more slowly than in their untreated counterparts. And that’s because before the drought, they were able to make the most of the resources in their environment, so they’re more prepared for lean times.”

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It’s not just expansion that improves the health of plants that have mycorrhizal sidekicks, though. Some mycorrhizae can also help to break down nutrients found in soil, such as phosphates. That makes it easier for their partner plant to absorb those nutrients, the same way cutting up a meal into smaller bites makes it easier for us to eat. The presence of mycorrhizae can even help ward off plant pathogens like molds, making it possible to fight fungi with fungi.

Introducing Mycorrhizae to a Cannabis Grow

Chances are, whatever soil you’re growing in already has some mycorrhizae in it. But just because these fungi are present in a growing medium doesn’t mean they’re making the plants in it healthier. Mycorrhizae spores—the fungal answer to seeds—need to come into direct contact with a plant’s roots to colonize them. And since the spores are fairly large, they don’t travel easily through soil.

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That’s where mycorrhizae-rich supplements like Clonex Root Maximizer can come in handy. In outdoor grows where plants are susceptible to the whims of weather, a thriving mycorrhizae population can render plants hardy enough to make it through trying times. Even in indoor growing operations where conditions are more tightly controlled and monitored, mycorrhizae can provide an “insurance policy” of sorts against unforeseen malfunctions.

Mycorrhizae can help plants in your cannabis garden better resist stressors like drought. (Yarygin/iStock)

Depending on a grower’s methods, mycorrhizae may be more than an insurance policy. In organic grows, for instance, these fungi are instrumental in breaking down organic material into small enough parts that it can be effectively put to use by cannabis and other crops.

Whether you’re planting row after row of flowers or a couple plants for personal use (and consult the laws in your area on that front, of course), mycorrhizae can give your cannabis crop a boost. As events like droughts become increasingly common, this little-known partnership between fungus and plant could be the difference between a successful growing season and hoping for better luck next year.