Cannabis Science


How Mycorrhizae Fungi Benefits Cannabis Plants

If you have ever encountered mushrooms growing in your cannabis garden, you may have contemplated whether the sprouting objects are friend or foe. Obviously, the warm, humid growing environment must be inviting as the fungal protrusions begin popping up from beneath the soil. But are mushrooms good to be growing alongside your marijuana plants?

When we think of fungi in cannabis cultivation, often the first thought is dread. Mould spores multiply prolifically under ideal conditions in most grow rooms. High temperatures and sultry humidity levels encourage botrytis and other malignant fungal spores to reproduce. Without immediate intervention, these deadly fungi can quickly decimate a cannabis crop.

While some fungal species are detrimental in a marijuana garden, others provide mutual support to the plants. A valuable symbiotic relationship exists between beneficial fungi and cannabis plant roots called mycorrhizae. In this advantageous interaction, the plant feeds the hungry fungi, which in turn supports plant development.

Mycorrhizae relationships have existed for millions of years between various plant species and fungi. One example is mushrooms protruding out of decaying logs in a thick forest. The mushrooms are the ‘fruiting’ bodies of the fungi, encouraged to spawn by the symbiotic platform of the environment.

Interestingly, advanced research into marijuana cultivation unveils the benefits of mycorrhizae fungi on plants in several different ways. Not only does fungi support and contribute to a plant’s root system, but it also helps with nutrient and water uptake, disease resistance, and environmental impacts.

Checkin’ Out the Root Zone

If you have ever flipped a marijuana plant upside down and slid the pot off to survey root growth, a healthy white system of large, sturdy roots should be dominantly observed. However, taking a closer look at the pearly white tentacles exposes fuzzy little components called hyphae intertwined into a complex web of support.

This hyphae branching, referred to as mycelium, results from the mycorrhizal relationship between the cannabis plant’s root system and the fungus spores germinated from their collaboration. As the plant matures through its life cycle, the root system becomes an increasingly complex array of large roots with the smaller threads from the hyphae weaved amongst them.

By the time a mycorrhizal happy potted plant is ready for harvest, the root ball is often so dense, you can cut it with a knife.

How Does Fungus Help a Marijuana Plant?

Fungi is a basic life form dating back to the beginning of time found in many natural practices. Generally, the fungus is known for its decomposition activities of organic matter and assistance with yeast and fermentation reactions.

In the plant world, fungi play a huge role in aiding the root system. As hospitable hosts, mycorrhizal relations develop in a plant’s root zone to encourage fungal interaction. The roots provide the essential sugar molecules for fungi to survive while, in return, hyphae filaments spread throughout the system, building a supportive mycelium network.

Thin hyphal strands reach out far and wide to extract essential nutrients and water in the substrate. As the surface area of the root zone expands from their influence, uptake of these vital lifelines also increases. In addition, fungi build small reservoirs to increase the root zone’s water holding capacity while creating branching structures called arbuscules to exchange nutrients for sugar molecules.

As an added bonus, the mycelium branching becomes a fortress, protecting a marijuana plant’s root system from pathogens such as botrytis. With the help of fungi in a mycorrhizal relationship, plants become more resistant to environmental stresses such as drought or toxicity from excess salts or unwanted heavy metal particles.

Further enhancing the symbiosis, fungi excrete metabolic by-products containing glomalin which binds soil particles together. The presence of this glycoprotein results in better water retention, less erosion, and overall improvements to soil quality.

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Ecto VS Endo Mycorrhizae Fungi

Ectomycorrhizae fungi affect less than 10% of plant species. This symbiotic relationship creates the dense forests of conifers and the beautiful soil lying under a hardwood tree grove. These fungi reside in the rhizosphere of tree species, building a sheath of hyphae filaments around the roots.

Ultimately, the mycorrhizal fungi relationship builds an advanced network of mycelium, stretching out into areas of the soil where primary roots cannot reach. Interestingly, ectomycorrhizal fungi form the fruiting bodies of mushrooms found in heavily decaying forests.

Endomycorrhizal fungi also referred to as arbuscular, are benefactors found in 80% of all plant types. These active fungi spores germinate to form hyphae which penetrate a plant’s root cells. Once inside, the hyphal design readjusts to create arbuscules, unique structures formed for nutrient and carbohydrate exchange.

Also known as AM fungi ( or AMF), their contribution to plant development captures essential nutrients such as nitrogen, sulfur, and essential micronutrients, relaying them to the cannabis plant via the arbuscules.

Another vital element, Phosphorus, might be abundant in the soil. However, it is typically not found in a plant-available form. Fortunately, arbuscular mycorrhizal fungi play a symbiotic role in forming enzymes to break down large phosphorus molecules to upload the nutrient into the cannabis plant easily.

Building the Root System with Mycorrhizae

Introducing mycorrhizae fungi spores to a cannabis root system is accomplished through inoculation from a natural occurrence or an additive by a marijuana grower. Growers incorporating mycorrhizal spores early in vegetative plant growth ensures the symbiotic experience will be successful.

The best time to add mycorrhizal inoculants is during the first transplant as the cannabis clone or seed outgrows its initial pot. Continued applications of the spores in subsequent up-potting practices keep fungal populations alive and thriving as the marijuana plant progresses into the flowering stage.

While mycorrhizal fungus spores exist in nature, outdoor growers can jumpstart the fungal activity in their gardens by inoculating the soil during the initial planting time. Even hydroponic cannabis growers can capitalize on mycorrhizal reactions with frequent dosing of fungi spores into their growing medium. The key to fungal success in hydro growing set-ups is an abundance of oxygen and regular replenishments of mycorrhizae spores.

In the great outdoors, fungus spores can sit idle in the soil for years, waiting for a healthy root to come along for it to infect. Once direct contact is made, though, changes begin occurring rapidly down under.

When the plant recognizes the fungi’s presence, it starts feeding the benefactors with the necessary sugar molecules the spores need to grow. In turn, the fungal inhabitants germinate and begin colonizing the roots.

As the symbiotic relationship begins to unfold, a massive root system with the added mycelial support from the fungi provides a solid base for plant development. A large, vigorous root structure is the foundation for a big, healthy cannabis plant. And in turn, a big, healthy plant will result in a bountiful harvest.

Mycorrhizae Fungi Benefits Cannabis Plants

Feed the Fungi and the Fungi Will Feed the Plant

Cannabis plants have a built-in system for feeding themselves. Through the energy exchange of photosynthesis, they take in light, water, oxygen, and carbon from the atmosphere. In turn, the plant takes the light energy, converting it to other forms of energy, such as creating carbohydrates to feed itself.

Unlike plants, fungi are unable to synthesize their own food. Therefore, as a source of nourishment, they rely on the mycorrhizal relationship within the plant. As mere survival tactics, fungi trade their supportive input to root development for the sweet sugar required for their existence.

In a mycorrhizal symbiotic ecosystem, all parties contribute to benefit their existence. The plant feeds the fungi carbohydrates to sustain its survival, and in turn, the fungi support their active role in the root zone. Providing a pleasing environment for abundant photosynthesis, adequate hydration, and quick nutrient uptake guarantees a plentiful harvest from a prized cannabis cultivar.

Choosing the Best Mycorrhizae Fungi for Cannabis Plants

Thankfully, science has come before us, uncovering the symbiotic fungi which accentuate cannabis plant health. All agree that the endo-arbuscular mycorrhizae fungi are the spores or hyphae filaments most beneficial for this particular plant.

However, terminology on fungi species is a bit unclear. For example, Glomus intraradices and Glomus mosseae are the fungal species most recommended. However, listed on many sites as the ‘new’ names for the Glomus species, Rhizophagus Intraradices and Rhizophagus Mosseae are also mentioned.

Given the size, structure, and vast number of fungal species inhabiting our planet, it is easy to understand how difficult a mycologist’s job must be.

Post author
Charle Thibodeau
Charle’ Thibodeau is a freelance writer with almost a decade´s experience, specializing in cannabis content for the past two years. A strong motivation to educate, inform, and promote the culture surrounding this miraculous plant is her earnest mission.
See more from Charle Thibodeau

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