Mycorrhizal Inoculant – Hard To Spell, Easy To Use
I use mycorrhizal inoculant in my organic garden almost every time I plant and seed. I wouldn’t plant without it.
Over 95% of plant species form symbiotic relationships with mycorrhizal fungi. The fungi provide nutrients and water to their host plants in exchange for carbohydrates and other goodies.
In fact, many plants will trade more than 50% of their carbohydrates with these fungi and other microbes.
Mycorrhizal fungi greatly improve soil characteristics, and are among the most important microbes that form relationships with plants.
This is another of those microbes that should be in our soil, but often isn’t anymore. In soil that has been tilled, compacted, water logged, treated with chemicals, or left without plant cover, mycorrhizal fungi may be seriously lacking.
They aren’t present in imported topsoil or potting soil mix either, and don’t multiply in compost. In any of these scenarios, they need to be added back to the soil, especially when planting or seeding, as they’re essential to optimum plant health.
We can inoculate our plants with mycorrhizal inoculant by taking just a small bucket of soil from a healthy environment that contains the right fungi, or by buying mycorrhizal fungi products from a garden center or online.
While the first method sounds like more fun to me, I’ve always gravitated to the second because I know what I’m getting.
Types Of Mycorrhizal Inoculant
There are two main categories of mycorrhizal fungi. Over 90% of plants form relationships with endomycorrhizal fungi, also called arbuscular mycorrhizal fungi.
You need them for most of your vegetables, grasses and many ornamentals.
About 5% of plants, including many conifers and some deciduous trees, form relationships with ectomycorrhizal fungi.
When you’re planting a mix of plants, you can often buy a mixture of endomycorrhizal and ectomycorrhizal fungi and just use that for everything.
How To Apply Mycorrhizal Spores
The best time to apply mycorrhizal inoculant is at the nursery during the plant production stage, but since your plants probably didn’t have that done, the next best time is at planting/seeding/sodding.
This will allow you to establish contact between the fungi and plant roots, which is important because that’s where the relationship occurs.
There’s no benefit to foliar feeding with mycorrhizal fungi, as they need to touch the roots. We can, however, mix them with biostimulants before application. Mycorrhizal products shouldn’t need to be applied more than once to each plant, unless your management practices are harming them.
Rub the fungi directly on the root ball if possible, or sprinkle in the planting hole.
For seed, mix it dry with the seed before spreading.
For sod, get a powder form of the fungi, mix with water, and spray it on the soil right before you lay the sod, or even better, right on the bottom of the sod. You could spray it on afterwards as well and water it down to the root zone.
While not as good, the other choice is to apply the product to existing landscapes. The powder form is best for mixing with water to get the spores to infiltrate into the soil.
For turf, it’s better to do this right after aerating so more of the spores get down to the roots. Otherwise, it can be watered in, but will not be as effective on heavy clay or very compacted soils.
Vegetable Plants That Don’t Use Mycorrhizal Fungi
There are some plants that generally do not form relationships with mycorrhizal fungi. The most important for vegetable gardeners is the Brassicaceae family:
- broccoli
- brussels sprouts
- cabbage
- cauliflower
- collards
- kale
- mustard
- rutabaga
… and members of the Amaranthaceae family:
- beets
- swiss chard
- lamb’s quarters
- quinoa
- spinach
- purslane
- amaranth
So that’s the basics of how to use mycorrhizal inoculant. Any questions? Have you used it before? Let me know below.
Or check out my more detailed mycorrhizae article.
Great presentation Phil! I recently bought a product called ‘Myke’ (or Mike?) but it seemed more like peat moss. I am wondering if this brand has only a little bit of actual Mycorrhizal fungi with lots of peat moss as a filler?
Myke is not bad. The carrier is necessary to help with application, so I don’t think you need to worry about two much filler with that brand.
Myke is the only commercially available source of micorrhizae in Canada. The spores are nearly invisible to the eye, so they mix it with a sterile “filler” for application purposes. Don’t use it like fertilizer… you only need a couple of spoonfuls to plant a tree.
Who sells it in Canada?
Not sure if anyone sells this product, but here’s another one: http://www.gardenerspantry.ca/microorganisms/mycorrhizal-fungi.html
should it be used during flowering stage to? or just seedling & veg?Ive been wondering if i should be adding it to my flower nute mix?i have been,& i dont notice any problems but? what ya think?
If it wasn’t used during planting/seeding, it can be used any time after, including during flowering. There’s no need to use it every time you fertilize, but it doesn’t hurt.
Keep in mind that mycorrhiza is a living organism. It only grows when it makes contact with plant roots. The fungi provides the plant with nutrients, and the plant provides the fungi with carbohydrates from photosynthesis (since the fungi cannot photosynthesise.)Don’t waste your money by applying it like a fertilizer. It must be applied to the roots. For established perennials, trees and shrubs you may cause damage by trying to apply it at the root zone; disturbing the soil will kill any fungi that are already growing there. For annuals and vegetables, it”s best to apply it at planting time when the roots are already exposed.
You’re right Lynne, but the very fine powders can be watered in to established gardens unless your soil is very compacted – no soil disturbance necessary.
Phil, I have been using Myke when planting outside with great results, is the fungi effective in a aquaponics set up where there is no soil in the growing media (after germination). Also your thoughts on aquaponics, any good sites about set up and equipment etc.?
I don’t know much about aquaponics, except that fungi are helpful.
Hi Phil, You suggested that Plant Success Granular Mycorhizae Inoculant is probably okay since you’ve determined who manufactured the mycorrhizal spores. What I am unclear on is how to apply this since it is not a powder. I am guessing I need to till it in. Is that accurate?What would the application rate be for applying to the soil before planting if you have any ideas? Can’t tell from the amazon listing and need to determine how much to buy.We are in SC and will plant a wide variety of vegetables from seed. Doesn’t seem as though I’ll be able to assure contact with each seed using the soil-mixing method and seems like I’ll need to use more product. Nevertheless I don’t see any other options on Amazon and I’m also not finding any organic gardening centers in this area.What are your thoughts if you would?Thanks!Allen
Hi Allen, if you’re applying during seeding, you could incorporate it into the soil or it might be much easier just to mix it with the seed before seeding. You don’t need to have it contact each seed, just be in the general vicinity in the soil. The roots will find it, so there’s really nothing to worry about there. Go to plant-success.com for application rates for that particular brand.
Hi Allen, if you’re applying during seeding, you could incorporate it into the soil or it might be much easier just to mix it with the seed before seeding. You don’t need to have it contact each seed, just be in the general vicinity in the soil. The roots will find it, so there’s really nothing to worry about there. Go to plant-success.com for application rates for that particular brand.
Hi Phil,I’m very much new to this, so forgive me if this is a silly question… You list some plants which do not form relationships with mycorrhizal fungi. Is that to say they don’t care wether or not they are there, or would they benefit from not having it in the soil at all?
Hi Elias, I’ve never seen evidence of any effect. My understanding is that the fungi don’t substantially help them or hurt them.
It is best not to have any mycorrhizal near them. It can inhibit their growth. Best to plant these in another separate part of your garden.
We’ve asked a couple of soil scientists about this over the years and they weren’t aware of any effect at all, but if you have some info on this, please let me know, Tim. Thanks!
Hi Phil,Thanks for the great info. I have an allotment garden since last summer, and don’t know what the former gardeners planted where. Last year I lost all my tomatoes except a ‘wild tomato’ to late blight. Now all my tomato plants again have late blight (at least i got to harvest a few first this summer). All the neighboring plots also have it, including some who have their tomatoes in ‘houses’. I was thinking of giving up on tomatoes… until I heard of a product containing ‘Trichoderma harzianum’ which is meant to form a symbiotic relationship with tomatoes and prevent late blight. However it costs 70 euro, and comes only in a 1 kilo package (at least what i can find in germany…)Have you heard of or have any experience with this fungus? The company that sells it says it needs to be reapplied every year – but most germans turn their soil every year. Do some fungus’s get killed by winter?
Trichoderma can be useful, but I would take more of a holistic approach instead of just adding one species. If you can get your soil healthy, the blight won’t cause problems. Quality compost will help, and a straw mulch, as well as regular applications of aerated compost tea during blight season. And then – it’s too advanced to explain here, but I would test your soil with a good organically-minded lab and get the soil fertility balanced out. Blight is partially a phosphorus deficiency in the soil, so if you can get your hands on some rock phosphate, that will help.
In the UK, we have a company that sells Trichoderma in smaller quantities. Try The Nutrient Company (TNC). They also trade on Amazon. I’ve found their products work well.
Best of luck
Hi Phil, Do mycorrhizal fungi form relationships with weeds?
Actually many weeds do not form the relationship, so they often thrive on mycorrhizal-deficient soils when the plants you’re trying to grow don’t.
Hi Phil,I have been trying to find out for some time but no one seems to know the answers. If I innoculate a perennial vegetable such as garlic with mychorizae, is it likely that the fungi will survive when I dig up the bulbs dry them and then grow again when I replant the bulb? If I post the bulbs to a friend is it likely that the fungi symbionts will also be posted with the bulb and innoculate the garden it is planted into?Also, will sulphur damage mycorrhizae? I have a pH issue and am undecided if I should use sulphur or not for fear of damaging the fragile fungi in the soil.
My understanding is that the mycorrhizal fungi may very well survive when dug up/replanted and when sent to your friend. There could be some dormant propagules that will break dormancy when the plant is actively growing again. Of course, it probably depends on the health of the fungi in the first place, and certainly on the environmental conditions during storage/transit.Sulfur can harm most microorganisms. You don’t want to manage pH anyway. Get a good, organic soil test done by a lab and manage the nutrients. If indeed you need sulfur and want to take it easier on your microbes, don’t apply to much. It may be best to apply no more than 2 pounds per 1000 square feet, and then focus on improving the biology to make that sulfur as bioavailable as possible.
Thanks for the info Phil. I thought that may be the case but have had no one to ask since I studied mycology over ten years ago. The difference mychorizae makes is amazing, especially when it is applied after a bush fire has been through.Do you buy inoculate each year or is there some way that you can make your own innoculant? Would it be possible to innoculate a potted plant and trim the roots each year to use to other gardens? I assume that if this worked you would use the root trimmings strait away and would not store them.
You can make your own inoculant, but it’s a bit of work to do well and I’ve always been happy to just buy it every year or 2. It is possible to inoculate a potted plant and use the roots (that’s how some inoculants are made), but unless you’re lab testing or using a microscope, you don’t really know how well those fungi are thriving in there. It would be a fun experiment, but to ensure results, I buy.
I was wondering, is there a difference in fungi that is used according to climate? I mean will the same product work in South Florida(where I live) as in Canada, or anywhere else for that matter? Or are different brands with different species of fungi used for different places?Also, if I were to use an innoculant on a newly made bed, would I just broadcast it and work it into the soil, or should it be applied to each plant as it is planted?
Many of the main fungi are prevalent all over the world, so the same product does work everywhere.If you are planting very densely, you could work it into the whole soil, but I prefer applying to each plant, and mixing it with seeds. Saves a lot of product.
Would you also use it in planting garlic?. Powder each clove as you plant it?
Yes, but I’d just put the cloves in a pile and sprinkle the powder on all of them at once. And actually I quickly soak them in a mixture of kelp and/or sea minerals and water first.
Hi Phil. I am planting in straw bales and buckets this year. Do you think the micorrhizae would still be beneficial ?
Absolutely Cindy, perhaps even more so.
Hello Phil… I live on Oahu in Hawaii. Everything that is sold here is shipped in containers on a barge and the container can get very hot in the sun. Can the Mycorrhizal spores survive in heat for a few days of shipping or am I buying a dead product?
Hi Gary, I wrote the guy who’s in charge of growing my mycorrhizal spores and here’s what he said. Hope it helps:”Hi Phil, the spores are pretty durable. The threshold is around 140 f when they are damaged. I would think they are ok on the barge, although I am not sure how hot it gets.”
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Since rutabaga don’t form micorrhizal relationship what about turnips
Nope, no brassica family plants form the relationship.
Hi! I was wondering if you had suggestions on the exact amount of mycorrhizae to use. If you could give me a measurement in number of grams per gallon plant, that would be wonderful. If you can’t thats also fine.
(I’m doing a science experiment on mycorrhizae and I need to have exact measurements. I couldn’t really find any answers online.)
Thanks!
It depends on which product you’re using, as they all have different spore counts, and probably other factors that influence application rate.
I have a blackberry orchard of about 75 plants that are about 5 years old. They’ve never done well or established great but small growth comes back every year. I have a powdered form of mycorrhizal and would like to apply it to the base of each plant then cover with mulch. Does it matter what time of year I do it? I want to do it now but want to make sure there wasn’t a better time. Another question: Does it matter if it is mixed with city water or does it need to be aerated/dechlorinated? Thanks!
Hi Becky, I’m not sure where you’re located, but I’d apply it after all freezing temps is done. And I always try to use dechlorinated water when possible.
Hi,
I am confused, because based on what I have seen, there is just straight-up “Mycorrhizal fungi” as in the brand “Xtreme” (is that a good brand, btw?) and then there is the “inoculant powder” which seems to come in smaller quantities. Is the inoculant powder meant to be multiplied…. if so, how??
Mycorrhizal fungi can come in powder or granular form (among others). The powder is often used when people want to apply it through a sprayer, while the granular is more often used just thrown into the planting hole, but both work well. What’s most important is the quality of the product. I’m not sure about the Xtreme brand – I’ve never analyzed it.
Hi
I want to use Mycorrhizal fungi for tomato seedlings
Is this possible?
Absolutely. Tomatoes benefit from the relationship.
thank you
Do you think which method is better
Rubbing mycorrhiza to the root and then transferring to the garden
Or pouring mycorrhiza in a pits
hello phil,
just wondering if these fungi are beneficial to strawberry plants? to expound on that when strawberry plants fruit it supplies sugar/ brix to the strawberries hence making it sweet, however to my shallow understanding, the plants also give carbs and sugar to the fungi as a form of symbiotic relationship, would this then be tantamount to less sugar/ brix made available to the strawberry fruits?
Thank You Very Much
best
Yes, the plants give food to the fungi, but then the fungi give food and water to the plants in return. The plants are much better off for it and their brix will go up. And yes, strawberries do form this relationship with mycorrhizal fungi 🙂
much appreciated!
Thank You Very Much
does chlorinated water from a hose damage the fungi?
In my view, it’s probably not ideal, but the manufacturer says it’s okay.
Do you think mycorrhizae impedes the growth of Brassicas, or is it just neutral?
It’s just neutral 🙂
Hi Phil,
It’s hard to find information online about all the different species of mycorrhizae within the endo & ecto spectrums. Focusing on the endo side for vegetable gardening, most products out there are 100% Glomus Intraradicies species of mycorrhizae for their ingredients. However other products (IE. Root Rescue brand) contain 9 different species of Endomycorrhizae fungi (and 9 of etco but irrelevant for vegetable plants).
Are we aiming for quantitative spore counts applied of Glomus Intraradicies species to the roots of our vegetable gardens, or is it better to focus on the diversity of fungi species for vegetable plants with a product like root rescue instead and let the species join with the host and multiply on their own? I’m confused why this information is so hard to find online since mycorrhizae is so heavily studied. It makes a BIG difference in product choices if we should be applying a diversity of potential endomycorrhizae to our vegtable/fruit/flower gardens!
Thanks!
Travis
It is a confusing topic. here’s what I wrote on my main mycorrhizae page, which isn’t much help (here’s the link):
“A point of controversy in the mycorrhizal inoculant world is diversity of species. Some people contend that G. Intraradices is really the only endomycorrhizal species you need, while others claim that a diversity of several endo species is better because each of them will do better in certain conditions with certain plants.
The latter has always made sense to me, because more diversity is usually better in nature, but after a lot of reading into this, I believe it’s not as important as you might think.
G. Intraradices is the important one. If a product has a few other species, as mine does, that’s probably a good thing, but not too big of a deal.”
For planting garlic cloves, I’m guessing it is best to put some mycorrhizae in the planting hole so when the garlic starts to root in the fall before the ground freezes so it gets the benefits rather than doing a soak of the garlic cloves and then planting in the ground. Or am I wrong?
Good question. I’m not sure it would make much difference.
OK, how about a slightly different scenario. Do you think there would be a difference putting some mycorrhizae into the planting hole or dampening the root plate (area the roots of the close grow from once in the ground) and dipping the end of the clove into mycorrhizae?
It seems a little more likely for the spores to be in the right place if you put them directly on the clove rather than into the soil.
Hi, Phil-
I am new to using these products. I am planting more natives in my yard and purchased the soluble form of Plant Success, as they were already in the ground. After using it once, they looked great. I contacted the company to find out how often to use it- they replied could use it as often as I wanted, as it does not hurt the plant, and just adds more of the spores. After a second application, several of the new plants (not the established ones I used it on..) have turned slightly yellow, and some have a slight purple tinge to the leaf edges (which I understand through reading that it could indicate low phosphorous). I have very heavy clay soil, but amended the planting areas with topsoil and mushroom compost. Could the mychorrhizae be causing the yellowing?
No, it almost certainly won’t be that product. You may have a phosphorus deficiency, though, whether temporarily due to cold weather or long-term due to insufficient soil phosphorus. That said, although purple is often taught as phosphorus deficiency, it’s not really that clear cut. Other deficiencies can lead to purple leaves, which is why soil and plant tissue testing are important, although I undestand – many home gardeners don’t want to get into that much detail.
Does anybody know particular tomatoes that work exceptionally well with myco, if at all any?
They should all benefit from Myco but I’m not aware of any that benefit more than others.
Thank you for the information so far. We planted a rose bush in the place where I know a rose bush flourished when I was a child. It’s never done very well, with insects eating away at the leaves. Would the rose bush benefit from an application of mycorrhizal fungi? If so, how should it be applied?
Hi Mary, roses often struggle when planted in the same spot as a previous rose. It even has a name, “rose sickness.” It’s conceivable that mycorrhizal fungi could help, as could Bio Ag, but it’s hard to say for sure. If you do try the fungi, you can dissolve 2 teaspoons in some water and water the soil around the plant. And of course, you can do the same with other plants in the garden, too. More info here.
Thank you!
Phil – I use BioCoat Gold from AEA on my vegetables, but I also grow a great many dahlias. Would it help to dust the tubers with this inoculant before planting them?.
Thanks.
Joanne
It’s a little concerning that the product contains 90% “inert ingredients.” I would want to know what that means. But the ingredients they do list – seaweed, calcium, humic acids, and microbes – would all be useful for tubers. Just don’t overdo it.
Hi Phil –
I bought a product called Myco Seed Treatment from Fedco Seeds, but it came without instructions. I’ve run across your site in my search for how to use it. It’s a blend of microorganisms and mycorrhizal fungi , but I can’t find out how much to use – when planting seed, or young plants. Any advice?
On their website, they say basically nothing about what’s in it. They do say “1–2 oz treats 100# of potato seed pieces, 4–8 oz/100# of other seed.”
Hi Phil – I am wondering if there is an equally beneficial inoculant that you would recommend for cabbage family and beet family plants.
They just don’t form the mycorrhizae relationship. They do still benefit from beneficial microorganisms, though, so using compost, compost tea, and EM ( https://www.smilinggardener.com/sale/effective-microorganisms-and-scd-probiotics/ ) are good additions.
Thanks!
Thank you for your replies, Phil!
I’m looking for a new nute line of products..was curious if you had any free samples, I would be glad to pay any shipping cost. Thanks for your time and hope to hear from you soon.
So sorry James, I don’t have free samples.
I’m familiar that it offers no benefits to cole crops but would it be of any benefit to garlic? Thanks.
Absolutely. I just used it when planting mine this week.
Thanks. I have 12 varieties and still prepping a bed, they’ll be close and didn’t want to use it if it were a waste, I’ve been using Mykos for the last few years with good results but it’s also susceptible to phosphorus and didn’t know what to put in the hole, it’s been years since I grew garlic intentionally–I thought a farmer told me back then to add bonemeal but it’s anywhere from 10 to 25 of P depending on brand and I thought I read over 8 or 10 of P can kill the mykos (pretty good at spelling except that word so will use the brand name spelling), I bought some 3-9-2 Dr. Earth for flowering plants, and have some others with very little or no P, like 5-1-1 and 12-0-12–everything I’m reading lately says garlic wants Nitrogen–so I’m still procrastinating! My intention was to fill the holes with worm casting sample bags I have sitting around here, a spoon of Mykos and some Azomite… plus a little of one of the 3 fertilizers…
I would just stick with the worm castings, mykos, and azomite. That’s neough. I wouldn’t apply much N-P-K unless you have a soil test saying you need any of them, and in that case, I would fertilize the whole soil area rather than just the planting holes. Can’t get into more detail here but hopefully that helps.