MycoGrow®: Mycorrhizal Fungi for Healthy Gardens

The term mycorrhizal comes from the Greek words mykes, meaning fungus, and rhiza, meaning root. Mycorrhizal fungi are fungi that have developed a symbiotic (mutually beneficial) relationship with the root systems of living plants, from garden vegetables all the way up to the trees of the Old Growth forests. Networks of mycorrhizal filaments envelop the seedling’s root structure, supporting the plant’s own ability to utilize water and nutrients in the soil. This relationship encourages healthy, vigorous growth.

Mycorrhizal Root Diagram

Roots that lack mycorrhizae (left) have limited ability to capture water, minerals and nutrients from the surrounding soil. Roots with mycorrhizae (right) have more surface area and greater “reach”, resulting in significantly enhanced uptake.

Sadly, modern techniques for clearing and developing land for human use tend to destroy mycorrhizal fungi, thereby reducing the ability of plants to thrive in man-made environments and forcing us to resort to fertilizers and other artificial means of promoting plant growth.

It is now possible to re-introduce mycorrhizal fungi to the soil, replenishing and re-vitalizing it in an effective, safe and 100% natural way. Fungi Perfecti’s MycoGrow products are designed for everyone from the home gardener/landscaper to the professional forestry manager, promoting faster growth, speeding transplant recovery and reducing the need for fertilizers and other additives. A number of different formulations are available, for all methods of plant cultivation.

(Please note: the mushroom species in our MycoGrow mycorrhizal fungus products have been selected for their speed of growth and maximum potential benefit to plants; they are neither gourmet nor medicinal mushrooms. While these species are not toxic or dangerous in any way, they are nonetheless not intended for human consumption.)

Our MycoGrow products contain mushroom species that are approved for use throughout the continental United States and Canada. However, our customers in Hawaii should be aware that they are not permitted in the state of Hawaii. We encourage all international customers to check their countries’ import regulations prior to ordering.

Additional Information

See a comprehensive list of plant species that benefit from endo- and ectomycorrhizae here.

Check out this amazing testimonial from one of our customers!

Read the story of Devon, a student who used our MycoGrow™ products in his sixth-grade Science Fair project, "Fungus or Fertilizer?"

If you would like to know more about mycorrhizal fungi, we highly recommend reading Dr. Mike Amaranthus' excellent article, "Mycorrhizal Management: a Look Beneath the Surface at Plant Management and Growth".

Frequently Asked Questions (FAQ)

What’s so great about mycorrhizae?
Mycorrhizae support plant health by breaking down hard-to-reach nutrients in the soil and assisting with water retention. Mycorrhizal fungi excrete unique enzymes and antibiotics that support plant health and allow for increased disease resistance. Because the mycorrhizae support plant health, they are most effective as preventative treatments with regard to disease organisms.

At what stage is it best to inoculate plants or starts?
The earlier the better. Early root and plant growth can benefit greatly from the mycorrhizae. For the earliest application, try our MycoGrow Endo/Ecto Seed Mix, which is applied directly to the seeds prior to planting. For established plants and starts, the MycoGrow Soluble and the MycoGrow for Vegetables are both mixed with water and used to drench the plant roots for inoculation. MycoGrow for Vegetables is also a great mix for applying directly to the soil and mixing dry. If you’ve got very large plants/trees, especially in pots, consider the Plant Success™ Tabs for easy inoculation.

What time of year is best for inoculation?
It is best to inoculate plants in the spring and the fall – because mycorrhizal spores are activated by root enzymes, it’s ideal to inoculate when the roots are most active.

How does temperature affect mycorrhizal spores’ viability?
If temperatures are below 40 °F (4.4 °C) when you inoculate, the spores will remain dormant. (Still viable, but inactive.)

Unless they are exposed to sustained temperatures above 130–140 °F (54.4–60 °C), mycorrhizal spores will remain active and viable for inoculation, even in warm climates.

Will mycorrhizal colonization spread?
Somewhat, yes. Once mycorrhizae have colonized about 30% of the existing root structure of a host, they will continue to spread to the remaining system. (So, if you inoculate even part of the root mass, it will spread if it can.)

Mycorrhizae will branch out over time, assisting neighboring plants with nutrient and water absorption/retention. That being said, this is a slow process. If you want to ensure colonization, it’s best to inoculate each plant to get it going.

Single species or blend – which is better?
Blends are better. Different mycorrhizal species specialize at different things – some excel in antibiotic production, others are stronger with regard to nutrient availability. Having diverse species colonization leads to a broader, more comprehensive mycorrhizal support network.

What is the shelf-life of the spores in MycoGrow?
Two years at full viability, after that, they’ll start to be less viable. Store the powdered product in a cool, dry location when not being used. (Do not place in fridge, as it will increase condensation within the container.) As a rule of thumb, you can increase the rate of inoculum by 10% after two years, and that should compensate for decreasing viability. (So, use 10% more in year three, and keep adding from there.)

What bout native/non-native fungi for my area?
There is nearly no genomic difference between the various populations of endomycorrhizae found around the globe.
Mycorrhizae are very prolific, and species can be found in healthy soils around the world. Some states/countries like Hawaii, New Zealand and Australia have import restrictions. Please check with your customs/agriculture departments prior to ordering.

How does the soil itself affect mycorrhizal growth?
For the most part, mycorrhizae can grow anywhere that plant roots can grow. They are extremely helpful to plant hosts in poor soil areas.

Very high levels of phosphorus can discourage mycorrhizal activity. (This is specifically with regard to available phosphorus levels above 70 parts per million (ppm), which encourage dormancy rather than active growth.)

What kinds of things should will negatively challenge mycorrhizal growth?

  • Tilling or excavation
  • Fallow soil
  • Pavement
  • Chemical soil fumigation
  • Chemical fungicides
  • High phosphorus fertilizers at time of application


Will fertilizer be needed after inoculation with mycorrhizae?
On average, treated plants will use/need 20-30% less fertilizer and water. Increased uptake by plants leads to more efficient use of resources. For this reason, many users find that they are able to reduce or even eliminate some supplementation in their inoculated crops.

If fertilizer is used, it’s best to avoid fertilizers with very high levels of phosphorus (above 70ppm), as they will encourage lethargy in mycorrhizal growth.

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