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Adding Mycorrhiza Fungi to Compost Tea

I’m interested in adding mycorrhiza fungi to my compost tea. I’d like to apply this blend to my fruit trees. Would this be beneficial? I assume that if I was to do this, then it should not be applied to the leaves of the fruit trees, but rather the roots and surrounding soil only.

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Dec 24, 2011
It’s Best to Add Mycorrhizal Fungi at Planting
by: Compost Junkie Dave

Adding mycorrhizal fungi to plant systems definitely has a lot of merit, however, these benefits are highly dependent on “how” and “where” you apply the fungi.

Ideally, you want to apply the fungi directly to the roots of your fruit trees (away from direct sunlight), so this would have meant adding the fungi pre-planting. There are several ways you could have done this: 1 – You can allow the root ball of the trees to soak for 5 minutes in a mixture of mycorrhizal fungi and compost tea (or fungi and water); 2 – You can grab a handful of mycorrhizae powder/granular mix and rub it all over the roots of your trees before planting.

I would recommend doing this for any trees you plant in the future, but since we’re talking about adding mycorrhizae to planted trees, we have to take a different approach.

Since the fungi thrive when they come in contact with the roots of your fruit trees, I’m going to recommend you inject a mix of compost tea and fungi (see Note 1 below) directly into the soil around your trees. Do this at the drip-line of each tree. Depending on the number of trees you have, you may want to hire an arborist to do this for you. They would use specific soil injection equipment. Otherwise, if you want to do this manually, you’ll want to dig a trench around each tree (at the drip line) that is approximately 6″ deep by 4-6″ wide. Fill this trench with a mix of high-quality compost and mycorrhizal fungi. When your tree roots extend into this nutrient- and fungal-rich zone, they’ll be happier than pigs in S%$#.

Note 1 – Mycorrhizal fungi will not increase in number when added to compost tea. More than likely, they won’t even survive the brewing of your compost tea. Why? Because they work in a symbiotic relationship with plant roots…no root contact = unhappy fungi. So if you’re going to add them to your compost tea, do it immediately after brewing and right before applying your tea to the plant roots (ideal), or as a soil drench (not ideal). If you do make a soil drench, please do it away from direct sunlight (early morning or early evening).

Note 2 – If you are really keen and want to experience true magic, try the following…
– mix the fungi with high-quality compost
– apply this mixture 1-2″ thick under the canopy of each tree
– cover this compost/fungi mix with a 3-6″ layer of mulch (e.g. wood chips)
– Sit back and watch nature work Her magic
(This technique mimics a natural system much more than the advice provided above)

Dec 25, 2011
Mycorrhiza fungi
by: Gardener Ed

What a great idea; adding mycorrhiza fungi to fruit tree root systems.

I searched the site for other info on mycorrhiza and was not successful. So I’ll ask my questions here:

1. are there different species of mycorrhiza and if so which are best for fruit trees?

2. where can one acquire mycorrhiza fungi/spores?

3. can the be harvested from indigenous plants growing nearby?

Dec 26, 2011
Arbuscular Mycorrhizal Fungi & Endo-mycorrhizal Fungi
by: Compost Junkie Dave

I searched the site for other info on mycorrhiza and was not successful.

To be quite honest, we haven’t written much about the topic yet.

I’m also considering adding a search function to our site in hopes that it will make it easier to find information. What do you think, good idea?

So I’ll ask my questions here:

1. Are there different species of mycorrhiza and if so which are best for fruit trees?

Yes, there are different species of mycorrhizal fungi – ENDO-mycorrhiza and ECTO-mycorrhiza (arbuscular mycorrhizae). More than 90% of plants form symbiotic relationships with endomycorrhizal fungi, whereas ectomycorrhizal fungi form relationships with approximately 2% of plants. The following is a list (from of some common plants and the specific type of fungi associated with them – Mycorrhizal Fungi Plant Relationships You’ll notice that the majority of our edible crops, including most fruit trees, form relationships with ENDO-mycorrhizal fungi.

2. Where can one acquire mycorrhiza fungi/spores?

Check out for purchasing details.

3. Can they be harvested from indigenous plants growing nearby?

YES! Absolutely! This is one of the best ways to inoculate your plants during transplanting or potting. If you have a well trained eye, you may be able to verify that the soil you’re planning to use as an inoculum is populated with fungi. However, most people don’t have a trained eye, so here’s the next best way:

Find a plant, or plants, that are in the same family as the plant you’d like to inoculate. Make sure that the root systems of these donor plants have not been disturbed for several years. Remove some soil from around the roots of these plants. It’s okay, and sometimes preferred, that you take some root mass with you (just be respectful of the donor plant). Add this soil to the root zone of your transplants. If you’re inoculating potting soil, don’t mix this inoculum throughout the entire pot; instead, add it directly around the root ball of your plants. Remember – No root contact = unhappy fungi.

Please note that this “natural inoculating” technique is more easily accomplished with perennial plant systems than annuals. Why? Because the fungi have had more time to adapt and proliferate in a perennial system than an annual one.

For more information on this topic, check out the publication by the University of Alaska Fairbanks I just posted on our Facebook page.

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