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How do you choose the right mycorrhizal product for better business

Cannabis plant

When it comes to competitive markets, the cannabis industry is up there. To increase profitability, growers are trying to find their edge. Most businesses and cannabis lovers want to discover a way to produce better quality cannabis at a reasonable cost. But how?

This is when active ingredients come in. Active ingredients, such as mycorrhizae, offer incredible advantages for your culture, and ultimately for your business, which should not be neglected.

Benefices of mycorrhizae

Table 1

However, with all the mycorrhizal products available on the market, how do you know which one is reliable and will provide actual results? Some might benefit your plants, but most will have no effect on them. Although mycorrhizae are a fairly well-known topic in the industry, they’re still not fully understood by the community. That, paired with the wide selection of products available to growers, makes it hard to make an informed choice when buying a mycorrhizal inoculant.

So what considerations should you have when assessing whether a mycorrhizal product is worth the investment?

Propagules VS Viable Spores

What makes the number of viable spores more important than the number of propagules?

Let’s start from the beginning. Mycorrhizae are a beneficial symbiosis between a mycorrhizal fungus and the roots of a plant. Many positive effects of this symbiosis on cannabis plants are well established (Table 2).

When viable mycorrhizal spores sprout, they develop hyphae which explore the soil for a root to colonize. Vesicles and arbuscules are created once the hyphae enter inside the root. More hyphae will then grow out of the new vesicles and spread in the soil to attain nutrients and water. The nutrients and water will be brought back to the plant and exchanged for carbon (lipids/sugars).

Roots with mycorrhizae

Table 2

When mycorrhizal products are identified as propagules, it entails that they are not filled with exclusively viable spores. Why does that matter?

Like seeds for a cannabis plant, spores are how fungi reproduce. Only viable spores can create a mycorrhizal symbiosis with the roots. Because of that, a product, to be worth it, needs to indicate that it contains viable spores.


  • Mycorrhizal fungi reproduce through round SPORES that contain lipids. These spores are more resistant and live longer than other propagules. It is important to note that not all spores are the same when it comes to resistance and potency. Companies include all spores in the propagule count.
  • VIABLE SPORES are the spores that are able to colonize the roots. Provided they have physical integrity, both the spores (in the product) and the vesicles (in the root fragments) can be viable and are counted in the propagule count.
  • Growing out of spores are HYPHAE FRAGMENTS. They have short lifespans and are vulnerable to stress. They are not always included in the propagule count.
  • NON-VIABLE SPORES are heterogeneous or lipid-free spores. They are not capable of germinating or colonizing a plant. They are included in most companies’ propagule count.
  • PROPAGULES are any portion of a mycorrhizal fungus (including all the aforementioned) which can connect with the roots of the plant to create symbiosis. However, not every propagule has the same capacity and strength to form symbiosis. The registration process allows companies to include all propagules (not just viable spores) in their count.

Comparaison microscope

Table 3

In short, you should always seek a mycorrhizal inoculant that indicates its concentration in viable spores, or at least guarantee its propagules’ viability.

Not All Mycorrhizae Products are Equally Effective

Not all mycorrhizal products are equally effective, especially when it comes to short crops like cannabis where you have little room for mistakes. To see its full benefits in the plants, the product needs to work fast and well. There are three factors to consider when choosing a mycorrhizal inoculant:

Viable Concentrated Close
It needs to be viable (alive) when it's finally time to use it and remember only a viable spore (fungi seed) can colonize a root efficiently. It needs to be concentrated to get a stronger reaction and a better chance to connect efficiently. It needs to be applied close to the root system to allow the symbiosis to happen as quickly as possible. 

Table 4

Designed for cannabis growers, PRO-MIX® Mycorrhizal Inoculant CONNECT™ has been specially created with these three factors in mind: viability, concentration and application. It’s the most concentrated inoculant on the market with its 6000 viable spores per gram. So, when transplanting, applying CONNECT™ as a slurry on rooted cuttings will put around 30 000 viable spores in direct contact with the roots. The symbiosis will take place, and quickly.

Analysing the Product Performance

Testing two different products for comparison purposes can be a difficult process. Many cannabis growers will apply different products to different plants and set up a demonstration to verify their efficacy. However, with all the variables and possible fluctuations in compaction, lighting, fertilization, temperature, ventilation and more, testing various products that way will not give statistically significant results.

Mycorrhizae from a microscope

Germination and root colonization of mycorrhizal spores.

In controlled conditions and following rigorous scientific protocols, Premier Tech analyzed the product efficacy and viability of several mycorrhizal inoculants available on the market. Premier Tech was verifying if the product tested contained the guaranteed number of spores they indicated, and if these spores were capable of colonizing a cannabis plant in a timely manner.

PRO-MIX® CONNECT™ was the most concentrated product (proven by a spore count test), and by far! It was also the only product to colonize every single plant, 100%, with a 40% root colonization rate. The nearest competitor colonized 63% of plants with only 5% root colonization average. Out of seven products tested, four did not colonize plants at all!

For a better terpene profile, bigger yield and higher cannabinoids concentration, the cannabis plants’ root system is essential. Spending more for a great quality mycorrhizal product with a high viable spore count is worth it in the end. It ensures faster growth with less vegetative time, increased resistance to stress, larger yield, enhanced trichome density, better potency (THC, CBD, etc.) and improved terpene profile.

Multiple formats of PRO-MIX® CONNECT™ are available in Canada and the US.

PRO-MIX® is a registered trademark of PREMIER HORTICULTURE Ltd.

For more information, contact your Premier Tech Grower Services Representative:

   Ed Bloodnick           Nathan Wallace-Springer           Lance Lawson           Victor Brantly

Ed Bloodnick
Horticulture Director
South Eastern US,
Japan and Overseas 

Nathan Wallace-Springer
Horticulture Specialist
South Eastern US

Lance Lawson
Horticulture Specialist
Western US
and Western Canada

Victor Brantly
Horticulture Specialist
Central US

Troy Buechel Susan Parent  Jose Chen Lopez  

Troy Buechel
Horticulture Specialist
Eastern and
North Eastern US

Susan Parent
Horticulture Specialist
Eastern Canada and
North Eastern US 

Jose Chen Lopez
Horticulture Specialist
Mexico and
South Western US






PRO-MIX® is a registered trademark of PREMIER HORTICULTURE Ltd.

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