The Power of Mycorrhizal Inoculants on Indoor Cannabis Crops

By Rich Hamilton
Published: December 2, 2020 | Last updated: December 7, 2021 10:44:55
Presented by Premier Tech Horticulture
Key Takeaways

Mycorrhizae are credited with creating vast underground systems that allow massive tracts of natural growing plants to thrive, so imagine what it can do for your indoor cannabis crop. Grow expert and author Rich Hamilton gets to the root of the benefits of using mycorrhizae inoculants in your growroom.

When it comes to growing cannabis, achieving best results with the heaviest, most resinous buds is everyone’s goal. While there are a lot of products that can help you with your garden goals, there is a range of products that sometimes get overlooked.


Not only are these products proven to boost your plants in a multitude of ways, but they use a natural and organic path that works in harmony with your normal feeding regime to give you bigger, better results. That miracle range of products is from the mycorrhizae family.

Mycorrhizae means “fungus root” and is part of a complex group of naturally occurring fungi that can be used to get the most out of your cannabis plants.


Benefits of Mycorrhizae on Cannabis Roots

Mycorrhizae works on the most important part of your cannabis plant — the root system, an area that goes unseen and as a result is often forgotten. Maintaining a healthy root system is an essential part of producing high-quality cannabis. The root system is the foundation from which your plants will grow. Its primary function is to absorb water and nutrients and transfer them to the rest of the plant. The healthier and stronger the root system, the lusher and more vibrant your cannabis will be.

Often, we don’t link the symptoms observed on leaves or stalks as being a root problem. Once your root system becomes damaged, it is often mistaken for basic deficiencies, meaning you may never get to the bottom of the problem by adjusting your feed levels alone.

Mycorrhizal products can improve your yield and quality in a totally natural, organic way. The benefits include improved root growth and health, and an increase in flowering, fruiting, nutrient uptake, water uptake, and final yield. Which — let’s be clear — is exactly what we are here for when it comes to growing cannabis.


Mycorrhizae for Organic Cannabis Growing

Mycorrhizae is also a great tool if you are an organic grower as it can reduce fertilizer use, provide a resistance to salt toxicity, delay wilting, and reduce the risk of root disease and deficiencies. It protects against all manner of pests and provides a much higher success rate when transplanting.

There are hundreds of species of mycorrhizal fungi found around the world in differing soils and climates. The two most common classes are ectomycorrhizal and endomycorrhizal fungi. For herbaceous plants such as cannabis, endomycorrhizal fungi are the most beneficial.


Mycorrhizae are more than 400 million years old and helped facilitate life on land for the first vascular plants. Whole ecosystems would not be able to sustain themselves without the existence of mycorrhizae, and at least 80 per cent of all land plant species depend on it for survival.

Mycorrhizae and Cannabis Plants: A Mutual Benefit

Mycorrhizae and plants have a symbiotic relationship where the mycorrhizae fungi and the plant live and work together to mutual advantage. This relationship begins when fungal spores germinate creating threadlike microscopic structures called hyphae.

The hyphae enter the plant’s root system, colonize the root zone, and spread out densely into the growing medium, forming an expansive web called the mycelium.

The mycelium increases the root area of the plant anywhere between 300 to 800 times, sometimes more. Hyphae are so tiny that they squeeze their way into areas of the soil where normal roots would not be able to reach, making them extremely effective at collecting more nutrients for the plant.

The plant feeds the fungi by sending excess sugar it has stored down to the roots, where the mycorrhizae then absorbs it to sustain themselves.

The mycorrhizae need these sugars because they only exist underground and cannot perform photosynthesis by themselves, meaning the sugars from the plants are what keeps them alive.

In return for this offering, the mycorrhizae provide the plant with greater access to nutrients, especially those in the form of phosphates. The mycelium increases the root’s area of absorption and helps process nutrient sources in forms that the plant’s roots alone would not be able to access. It increases the take up of all essential nutrient elements but especially elemental phosphorus (P), zinc (Zn), manganese (Mn), copper (Cu), and water.

Read also:

A Vast Underground Mycorrhizal Network

In a natural environment, the mycelium of a single mycorrhiza can connect multiple plants, including plants of different species. Mycelium can also connect with other forms of mycorrhizae creating an underground system called a common mycorrhizal network.

Plants can signal their needs to each other through this network, communicating with each other and using the network like a transportation line to transport sugars wherever they are needed.

In the natural world, mycorrhizal networks can connect plants that are on opposite sides of a forest. A single mycelium’s hyphae can measure hundreds or thousands of miles. The strands of hyphae are so fine that there can be more than 124 miles of hyphae in two pounds of soil!

Mycorrhizae is Perfect for Hydroponic Cannabis

Mycorrhizae products are usually sold in powder or liquid form and most of the top-quality products available are approved for use with organic or synthetic fertilizers in soils, coco, and all hydroponic systems.

Mycorrhizae can be used from the very beginning of your grow, at every repotting stage, or even as a top feed. This makes it perfect for cannabis plants as it will support your roots from day one, whether you are growing from seeds or cuttings or just want to maintain a healthy strong mother plant.

Although a natural occurrence, mediums commonly used for growing cannabis indoors, including coco coir and those with a base of peat moss or bark, are not composed of and do not naturally contain any mycorrhizal fungi. Therefore, you should add it yourself via a mycorrhizal inoculant.

Mycorrhizae does have its tolerances and best-use conditions, performing at optimal levels when the environment is kept between 68-73°F, a pH between 5.5-7.5, and in an environment that has equal air to water ratio.

Some species of mycorrhizae can tolerate more alkaline or acidic conditions, however, try to choose a product that contains a blend of various types of mycorrhizae species, as this will make for a healthy mix that works efficiently in a range of varying pH conditions.

Hydroponic grow systems are often lauded as producing phenomenal results when it comes to growing cannabis, mainly due to the abundance of water and nutrients that the roots are constantly exposed to, so the use of mycorrhizae here is the perfect fit to enhance results even further.

There are mycorrhizal mixes specifically designed for hydroponic systems where spores and hyphae fragments are mixed with delivery media in liquid or powder form. Many generic formulations can be added directly to the hydroponic nutrient delivery, however, as the particles within the mix are small enough to pass through systems without clogging them up. If in any doubt, check the directions before you buy.

Mycorrhizal fungi do not generally reproduce in hydroponic systems, so you need to remember to add more inoculant to the nutrient delivery system as the roots develop throughout the life of the plant

A hydroponic system needs to be fully aerobic if you intend on using mycorrhizae, so oxygen levels should be maintained at 6-8 ppm via the use of air stones or bubblers, which is something you should be doing anyway to ensure your roots are benefitting from adequate oxygenation.

Phosphorus levels of around 70 ppm or more in a hydro system can result in fungal spores going dormant and not germinating, therefore you should carefully monitor phosphorus levels to encourage the presence of mycorrhizae. The presence of chlorine in your water systems can also affect the mycorrhizal growth and should be removed from water used in hydroponic applications.

The pH of water in hydroponic systems is also important. Most mycorrhizal fungi require a pH range of 5.5-7.0 to survive. Maintaining proper temperatures will maximize mycorrhizal colonization further so take not that mycorrhizal fungi thrive in temperatures of 65-75°F, which is the ideal range for most plants including cannabis.

Start Mycorrhizae Early

The earlier you start using mycorrhizae the better, as fungal spores can take several weeks to establish. By applying from the seed or cutting phase, colonization of your plants will occur quicker via lower dosage levels than if you were to wait until the plant is more mature. You will also see the benefits faster and be rewarded with healthier more fruitful cannabis plants and yields.

Most plants grow to their fullest potential when supplied with endomycorrhizal fungi; they produce either more crops per plant, larger vegetables, or more fruits and flowers. This makes mycorrhizae the perfect additive for growing cannabis as large flowering/fruiting plants is exactly what we want.

If you are looking for a little extra for your existing grow that is easy to use, provides an abundance of benefits, increases root mass, and is 100 per cent organic, then you really can’t go wrong with a mycorrhizal inoculant. It is by far the easiest, most effective, affordable solution to give you a helping hand throughout your cannabis grow cycle.

Give it a go on your next grow.


Share This Article

  • Facebook
  • LinkedIn
  • Twitter

Presented By

Logo for Premier Tech Horticulture

Written by Rich Hamilton | Writer, Consultant, Author of The Growers Guide

Profile Picture of Rich Hamilton

Rich Hamilton has been in the hydroponics industry for more than 20 years, working originally as a general manager in a hydroponics retail outlet before becoming an account manager at Century Growsystems. He enjoys working on a daily basis with shop owners, manufacturers, distributors, and end users to develop premium products.

More from Premier Tech Horticulture

Go back to top
Maximum Yield Logo

You must be 19 years of age or older to enter this site.

Please confirm your date of birth:

This feature requires cookies to be enabled