miccorrhizal fungi

Burwash Weald, United Kingdom(Zone 9b)

I have posted this over on soil and compost too, but I thought maybe someone here might have thought about this product too (can't imagine it isn't in the shops in the US if it is here). I am sure that our resident scienctist will have something to tell me about it - fingers crossed Sofer, over to you - on one thread or thother.

I have just been reading about a product that promotes mycorrhizal fungi - used in granular form when planting out/potting on plants, it claims to promote extensive root growth. The particular product I am looking at, Rootgrow is a UK based product, and says that all of its innoculant fungii are UK products. What do you think about this?

They also do a second product called Rootfeed which they are saying is a humate (not sure if I have that right, didn't have my notebook with me, just my glasses) - used as a liquid feed.

I do grow on organic principles, but wondering how this fits in? Sounded interesting, but in need of more info before really considering using it.

Here is a link to a classic thread on the subject http://davesgarden.com/community/forums/t/11392/ and he is a PNWer.

This message was edited Mar 22, 2008 2:06 PM

Kirkland, WA(Zone 7b)

Lots of reading to do. Thank you Laurie - I truly appreciated your link to the information.
Research is in order, that was back in 2001, so there should be more information gleaned from people's experiences available.

Burwash Weald, United Kingdom(Zone 9b)

that's what I am hoping Katye (and thanks for asking after the garden projects last week - I'm not ignoring you - I just don't have any pics to post right now - and too many barrow stories just gets Katie snorting at her screen and me looking like a dolt - I'm hoping to get a couple photos taken IF this weather improves a bit, but right now we have hail blowing in two opposite directions! Not great). Now back to mycorrhizal fungi - I think I have 3 questions in mind: can we use it in organically grown conditions (and should we want to). I use a lot of my home grown compost, complete with lots of lovely little red worms growing happily - thus making casts - does that mean I have a full load of fungii already going? And 3rd, I use purchased (sterilized) peat free compost for seeds, potting on, and cuttings - if that is sterile enough to have no seeds/bad stuff, would it be helped by a dose of mycorrhizal liquid

sorry - I got interrupted by an urgent terrier with a squeaky ball - gotta go

This message was edited Mar 22, 2008 6:38 PM

Kirkland, WA(Zone 7b)

question # 1 is my main concern. Chemicals are readily available, probably some are less "intrusive" than others. However, if I had something like this available to me, I would prefer to use it, instead. Without a whole lot of noodling: I would think that when using sterilized mix, the addition of such a substance would be beneficial. Need to research, though. Have you had issues starting seeds in this type medium? I have not - that I know of, humidity & warmth controls aside. But - if it would help, and meets the criteria concerns we have, why not? That's why I would like to experiment - I want to SEE it for myself. My brother is a scientist - I'll run this by him and see what he can offer.

Burwash Weald, United Kingdom(Zone 9b)

Thanks Katye - I also found this site with EVEN more info, but very interesting


I'll be interested to hear what others have to say - nice having a handy brother. Mine is a rocket scientist - no, honestly, he is a rocket scientist - so anything to do with dirt interests him about zero - well, except driving my other brother's tractor.

this is the bumpf from the package I was reading at the nursery - found this on the internet. As I have said on soil/compost thread - I'm just putting this here as a 'discussion document' not as advocacy - the verdict is still out

RootGrow Mycorrhizal Fungi Handy 75 Gram Sachet

This amazing new product supports new planting, by reducing, repotting problems in most plants,

Rootgrow supports plants during dry periods and actively extends the plants natural root system and nutrient absorption.

90% of all plants have depended on a beneficial group of fungi called mycorrhizal fungi to transport nutrients and water to their roots.

In the average garden it may take up to 5 years for these fungi to naturally colonise freshly planted plants. However if rootgrow is sprinkled in the bottom of the planting hole at planting time this effect will be achieved in 2-4 weeks,

Rootgrow is a completely natural product containing UK origin mycorrhizal fungi.

Mix 1:20 with the growing medium if small plants are being grown together (e.g. strawberries).

Plants suitable include roses, all garden shrubs, garden flowers, bulbs and vegetables.

Rootgrow will not help brassicas, rhododendrons, azaleas, orchids or heathers

The benefits to plants are,

one treatment lasts forever (as the plant grows the fungal partner grows)
rootgrow is easy to use (simply sprinkle in the bottom of the planting hole)
earlier and better growth (in 2-4 weeks after planting the mycorrhizal fungi can increase the active root area of plants by up to 700 times)
better uptake of fertilisers when applied after planting (the network of mycorrhizal fungi act like a net catching nutrients and preventing leaching)
increased uptake of obscure trace elements from the soil leading to increased plant health (the ultra fine fungal mycelium can unlock nutrients from the soil)
reduced mortality of plants especially specimen plants and plants that are difficult to establish (the extended root system feeds the plant from very early on in its life)
better drought tolerance (due to the vast fungal root making best use of all available soil moisture)

This message was edited Mar 22, 2008 7:57 PM

Kalispell, MT(Zone 4b)

My thoughts after reading the gentleman's ideas in Spokane is this. 'If you build it they will come'. Any environment that encourages mycorrhizal growth you will have it because it is in all healthy soil. So I would have large amounts of compost for the roots to benefit from and these organisms will be readily available.

Kirkland, WA(Zone 7b)

1st question: are there any plants for which this might produce harmful results?
2nd: possible to use with established plants?

I am in for a quick break, so I haven't time to read much, but will do so this evening. I am extremely interested as this could be a tremendous help to those folks that have less than ideal soil, but do not have time to wait 3 years for the soil to improve.
Inotherwords, those making Lasagne beds or something similar. I believe what I had read was primarily in regards to potted plants, and that is why I would like to try an experiment. Off to the soil I go!

Vancouver, WA(Zone 8a)

Coincidentally, I was at a talk by a retired Horticulture/Soils Professor/Extension agent today, and someone asked him about this. His response was that they are already in soil naturally. Unless you're growing in something like straight bark or sawdust, which won't have any, or any bacteria, etc, either. He felt that in those situations it would be really beneficial, and also in a container where you'd started with a sterile mix, inoculating the soil with a mycorrhizae would be fine. He also figured that sure, you could use some in established beds to get to an optimal density but that they should be present in regular soil anyhow. I sort of got the feeling that he felt newer beds, or beds heavily amended with organics like wood chips, bark, or sawdust would benefit most. I don't know that he's necessarily a specialist, but he did seem familiar with the idea.

Snohomish, WA

I think most of us have been adding fertilizers and mulches to our beds for years and I can't really see a use for this unless you are starting a new sterile bed, or sterile soil for pots. I am just an old farm boy, but the soil is everything. Sort of like adding Miracle gro to cow manure. All the good stuff is is already there.
And I too have a rocket scientist for a brother. He has worked on the last two Mars missions and can't say what he is up to now. Can't change the battery in his rv either!! Seems like the smarter he gets in rockets the dumber he gets in every day life. He says if it was up to him to build the rocket it wouldn't get to the pad!

Port Orchard, WA(Zone 8a)

Laurie1, I've been using the Mycorrhizae for about 3 years now. I use it on all my transplants, bare root and seedlings. I buy the Humic Acid and use it on all my hosta hybrid seedlings that I grow in my basement, over the winter. I also make up a solution of 2 rooting hormones IBA, NAA. so I get thick balls on my young plants. with the Mycorrhizae fungi on the roots. I get twice the average growth rate, as compared with not using it. Jim

Vancouver, WA(Zone 8a)

Speaking of fertilizers....Anyone seen this thread?

Burwash Weald, United Kingdom(Zone 9b)

Many thanks to all of you for your input - I am finding this very interesting.

Katye - yes, some plants don't want this treatment: orchids, brassicas, lilies and a couple others - if you have time, the mycorrhizae hyperlink above has a very good list of what likes it alot, what benefits, and what is averse/doesn't benefit from its use. Interesting list. Your second question, it can benefit established plants when you are transplanting them - you add the innoculant to the bottom of the hole and place the plant on top in direct contact - otherwise you would need to use a humate root drench or foliar feed to create/improve the environment for the existing mycorrhizae to increase. (This is my understanding so far - scientists jump in if I am off the line here).

Susybell - thanks for the info from the talk you attended - wonderful coincidence of timing. I think it is sounding as if these are acceptable products to use in line with organic gardening practices, but may not be necessary in established beds and gardens - it may be that using a booster would be enough: compost tea, or the humate rootdrench/foliar feeds.

NWG - I agree with you that soil is everything!! And bless those great big piles of homemade compost we all lovingly tend! The best resource of all, I'm just checking to see how to bring them to their full potential. And, phew, to know that someone else has a rocket scientist in the family - they are odd, well at least mine is - always has been and my guess always will be - I think it has to do with contemplating 'infinity' as the place where you work - I like earth better.

Hostjim - Use in the greenhouse is my main area of interest since we are presently growing a lot of plants for the wild area, and I thought it might be a good idea to give them that real boost of root growth. But since everything eventually gets planted out, I just wanted to be sure that it would be something I wanted to introduce into the garden. My garden is bounded on 3 sides by our fields, and I always think carefully about anything that might eventually transfer to those areas.

All really good and helpful information - keep it coming.

(Louise) Palm Bay, FL(Zone 9b)

fungi perfecti sells their version and features an organic farmer using their product.

Burwash Weald, United Kingdom(Zone 9b)

thank you lavender, I'll check that out. (since it is snowing right now, it'll stop me tapping my foot and pacing around for a bit)

Kirkland, WA(Zone 7b)

Ok - tapping of feet here, too. But while tapping & giving the "mom" look to the clouds, I was treated to watching a Blue Heron fly over my property. Magnificent & so smooth!
Lots of bird activity going on - perhaps the drizzle has become a spitting?
Hmmm...No such luck. Full-on drizzle.
here's a bit of "sun" for you:

Thumbnail by Katye
Port Angeles, WA(Zone 8b)

Katye...don't know what it is about the birds right now. We have a pair of red-shafted flickers who have decided that our roof/rain gutters/siding would make a good home so we are treated to intermittent sounds something like a rivet gun or jackhammer. And yesterday, while outsiding, there was a woodpecker who decided that Tim's aluminum ladder was the place to be. He pecked for HOURS and was not shy in the least. There has been a great deal of bird activity here as well. . .

Mountlake Terrace, WA(Zone 8a)

I think that these treatments are fine if you have no room for a little compost tea in your life. It all can be sold very fancily on the store shelves, marketed and put into 5 gallon buckets to take home, or something that we can do for free in our backyards.

We have been doing to our plants what we have been doing to our bodies for years. Feeding them nutrients, not foods. Like our bodies, our plants need food too, not fertilizer, but food. Miccorrhizal fungi are but one part of that food stuff. What our plants need is compost along with all the fungi, critters, nutrients and organic matter. Developers all over have been stripping topsoils off development sites, and leaving us with mineral soils, which have little to none of these constituents.

These soils can be developed into topsoils with the infusion of regular shots of compost and organic matter, and the plants will do better for it. It is possible to soak a shovelful of compost in a bucket of water for a few hours, and use that water to water the garden, which will provide much of the fungi, and water soluble nutrients, this is commonly known as 'compost tea'.

The miccorrhizal fungi are just part of the web, isolated to sell to the consumer for a low, low price, or one can hit the old compost patch and make a little tea. Both will effect the plants positively, but the tea is free and probably better.

Snohomish, WA

That's an old farm trick we used to do on a much larger scale. My Dad still is part owner of the old wheat farm in ND, and they would put a gunny sack full of compost and manure in to a 500 gallon sprayer and spray the fields once a month. Other than the diesel for the tractor, it was the most cost effective way to amend the soil. They still do it today. My dad is 80 and very stuborn! He couldn't change if he had to. But even in the worst summers the farm has always made a profit.
I do think it is just anouther way to spend more of your money. Of course it helps, but the compost tea does the same as Analog nicely pointed out. It would make a great experiment to try this on my next tray of seeds. In this corner, Mother Nature, and in the other corner Modern Science!! Winner take all!

Port Angeles, WA(Zone 8b)

My vote is on the Mother. . .

Port Orchard, WA(Zone 8a)

NWGordon, I'm ready to start making my compost tea, as soon as it warms a little. I hit all my gardens, in the spring, and summer. along with more compost or should I say Tagro has replaced my using compost because of the cost. $10yd versus $28yd for compost. Jim

Mountlake Terrace, WA(Zone 8a)

I both make my own compost, and use Gardner & Bloome Soil Building Compost to build up my soil. All the other composts that I have seen seem to be 50% or more mineral soil when the soil is bought in bulk. Is there a source for 80%+ organic compost by the yard? I sure would love to lower the cost of my G&B purchases, as the stuff is not cheap.

Port Orchard, WA(Zone 8a)

AD, when I was buying compost, I didn't ask for a analysis, it looked 100%. the Tagro I buy is 25% peat 25% sand, 50% bio solids. it works better than any compost I ever bought. of course, I add the tea every year and that adds the microbes and trace elements. Jim

Mountlake Terrace, WA(Zone 8a)

Might I say that I meant organic in the form of plant matter, not farming practices.

It sounds like you have 75% organic compost, Jim, which is pretty darn good. The only analysis I use is either on the bag, or in my hand. If it looks sandy, it does not have a good quantity of vegetable matter for me. The G&B Soil Building Compost seems to have little if any sand or silt in the bag. I like that, and would like to find a bulk source for compost of that quality on the east side of the pond.

Port Orchard, WA(Zone 8a)

AD, there's one that is over on your side I believe. Cedar Grove. Jim

Mountlake Terrace, WA(Zone 8a)


Cedar Grove compost now has plastic chunks in it. At least the last bag I got did. Never knew that plastic chunks were necessary for plant growth.

I want better than that stuff. Something that is as good as my G&B.

Port Angeles, WA(Zone 8b)

I was wondering where the plastic pieces in my bulb bed kept coming from. I loaded it up with Cedar Grove earlier this year and keep finding little tiny piece of green or blue plastic. That explains it.

Port Orchard, WA(Zone 8a)

AD, if you have a truck you could drive to Tacoma and get a load of Tagro. for $5. I also make my own potting soil with it I mix more peat + pearlite, vermiculite. I heat it in 1gal bags in the microwave for 13 minutes for use inside, just in case there are fungus gnat eggs in it. Jim

Vashon, WA(Zone 8b)

I also get Cedar Grove on occasion, for variety along with the horse manure that is so plentifully available. I haven't been happy with the little plastic pieces either. It seems like they must compost the plastic bags along with the organic matter. I have been tempted to find out if the Tacoma Tagro place would deliver to Vashon to see if I like that product better. I looked at their site some time ago, and seem to remember they have a couple different mixes available. I don't think I want one with sand, rather have straight organic matter.

This message was edited Mar 29, 2008 9:55 PM

Mountlake Terrace, WA(Zone 8a)

I am not interested in getting Tagro compost, as with the bio solids is very likely to be contaminated, as the bio solids come from treatment plants, which I am not worried about bacteria levels, as it has been treated with chlorine to kill bacteria and create chloramines.

But it has not been treated to remove heavy metals that come in from stormwater. The bio solids are where the heavy metals are concentrated. Of course this means that the amounts are known, and made to be negligable to our health, but I have no interest with eating heavy metals, or introducing it to my yard.

I would prefer that such solids are sent to the landfill, than introduced into my garden. Composted manure is far preferable, and free, just look on Craigslist for a source near you.

Port Orchard, WA(Zone 8a)

AG, I'll have to check out the metals. aren't some metals good for the plants? I wonder about the cow manure. my brother has a dairy farm in Tillamook Ore. and they use an awful lot of antibiotics, and hormones. I've seen ups trucks delivering them. like 10 cases at a time. and also if the manure isn't composted enough it's full of e-coli. that's what's in a cows stomach. Jim

Mountlake Terrace, WA(Zone 8a)

Some metals are, but some are not. And it can all be even weirder Cr +6 is soluble and toxic to all living creatures. Cr+3 is bumper chrome, and is not toxic or soluble.

But I don't want to drink street runoff, much less give it to plants I eat. My stormwater ditch grass clippings go in the garbage. The rest of the yard goes on my compost pile.

We get enough of a dose of metals from living in urban/suburban areas. I suggest that we keep the rest of them further away.

As to the antibiotics, I would think that is safer by far to use. And the E. coli? You got me. But none of the compost pundits seem to worry. One can easily find a farm on Craigslist to get manure from.

Kalispell, MT(Zone 4b)

It is not the antibiotics but rather the bacteria that have accumulated genetics for antibiotic resistance. There is a good article in Discover this last month that tells you all of the dangers. Farm manure is the most dangerous (according to Discover) source of Mersa and Ecoli resistant bacteria. I for one continue to use all of the above because if we assume by scientists and research to define what is "safe" we shall loose all of the sources of healthy soil.

Port Orchard, WA(Zone 8a)

thanks for your in put. I think I'll keep using the Tagro, but I'm going to call them about the metals and see what they say about it. so far they've answered all the questions about the concerns I had. thanks all, Jim

Vashon, WA(Zone 8a)

Hello All,

Just found this post. I was recently thinking about getting some Tagro stuff for my yard. Does anybody know if they will deliver to Vashon?

Also, how has you experience been with Tagro all these years?


Everett, WA(Zone 8a)

When I see bulk Cedar Grove "compost" in dirt yards, it looks like 90% wood shavings. Not enough "compost" to give it even a faint odor. The dirt yard guy shrugged and said "yeah, it's more like fine mulch than compost".

For this they want $35 per yard plus delivery charges? I think not.

I used to think "maybe the stuff in Cedar grove bags is better than the bulk stuff". Not if it has plastic shreds!

The sheis-meister at the Everett sewage treatment plant says that they GIVE Class A biosolids to cedar grove, and he's eager to give it to anyone else with their own truck, but they don't dry it and and bag it. I'm not worried about pathogens or heavy metals in Class A biosolids - the town town water supply is probably not monitored as closely as the sewage plant.

Everett, WA(Zone 8a)

One thing about root fungi: they benefit the plant most when times are tough. They help the roots hairs greatly when soil is dry, or very low in Nitrogen.

However, in fertile, well-watered soil, the plant doesn't need them and often the roots manage to decrease the numbers of mycorrhiza that live inside the roots and roots hairs. The plant doesn't need to supply them with energy if it can get all the water and N that it needs, on its own.

This is one reason why soil that has gotten plenty of nitrogen fertilizer is said to "kill" beneficial microbes. The plant kicks out the mycorrhiza since it doesn't need them, and they go back to living free in soil, but in much lower numbers.

I'm sure it's also true that heavily over-fertilized soil, especially saline or acid soil starving for lack or organic amendments, also have much lower numbers of soil microbes. THAT is damaged soil.

But when soil is merely well-fertilized with chemicals, it usually is not KILLING soil life (in my belief). It's just that there is less for them to do, and less food for them.

When the organic food in the soil (humus and carbon or "browns" in compost) gets TOO low through over-reliance on chemicals and not enough compost and too-intensive exploitation, THEN soil life decreases through starvation.

That's not good, but they have to be really depressed for many years before they have any trouble rebounding as soon as they get a shot of compost. I would call that temporarily reduced fertility, not "killing the soil organisms".

But once their numbers start declining through starvation, I would call it "bad soil management". Or "not being able to afford enough compost".

Lake Stevens, WA(Zone 8a)

Corey I agree with your musings. And I have a few more thoughts-

Mycorrhizae are living fungi, so a bag that has sat dry on a shelf, and cooked in a truck somewhere may not have much alive when you finally put it on your garden. Plus you don't have any way to know what they actually put in there. If anything.

Because many mycorrhizae are specific to the plant they symbiose with, the ones in the bag may have nothing to do with your particular garden occupants. Especially if they are from England! What seems more likely to help a new garden created with purchased products, which might not have much in the way of normal soil
inhabitants (including earthworms and pillbugs etc) would be some shovelfuls of nearby soil tossed onto it, from a happy and not too chemicalized garden. It is quite possible that the above-mentioned farmer who sprays compost tea on his garden, from his manure pile, is spraying enough bacteria, fungi etc to helpfully inoculate his fields. Of course fresh manure could indeed carry pathogenic E. coli and other nasties. Yuck.

Gardening in pots indoors, with packaged sterile 'potting soil' might benefit more from purchased mycorrhizae, as noted above by Hostajim. But usually we fertilize our potted plants. When they have used up everything in the potting soil, it is time to repot.

i guess I am a bit suspicious. Bio-Organics seems to be a major purveyor of this stuff. I just looked it up on the web. The jar has a label on it that looks like a prescription drug, so it all seems very scientific. You can buy a 1.5# trial size jar for $52.50. That will buy a lot of mulch. Or whatever.

Everett, WA(Zone 8a)

Some vendors make much of the fact that THEY sell SPORES while other people just sell bits of fungal hyphae chopped fine. Spores have a much longer shelf life.

Everett, WA(Zone 8a)

>> some shovelfuls of nearby soil tossed onto it, from a happy and not too chemicalized garden. ...
>> compost tea
>> manure pile, is spraying enough bacteria, fungi etc to helpfully inoculate his fields.

I agree with that. I use the "shovelful of soil from my happiest bed" method myself.

>> many mycorrhizae are specific to the plant they symbiose with,

That's probably true, but I think that many plants can get along with a range of symbionts. I'll look that up, it's a vague memory.

I am quicker to believe that some fungi are very specialized in what plants they do well with, since they can always get along well enough without a plant. But root fungi help plants greatly in infertile and dry soil, so i don't see much advantage for a plant to develop mechanisms that would reject all but one root fungi. Could be wrong!

I was impressed by some some soil micro-biologist - I'm not even sure what century he worked in. He was sure that it mattered more what soil CONDITIONS you had, than any attempts to decrease disease populations or inoculate beneficial microbes. His theory was that for soil organisms, to a first approximation, "everything is everywhere".

If your plants are not dying of a disease, it's because your conditions don't favor it's growth. It's not because there are "zero" spores of that disease in the soil, rain and air. There's never "zero" anything.

Probably ditto for beneficial root fungi. If anything closely related grew in your yard in the last 20 years, there will be "some" mycorrhyzae spores or hyphae usable to a new plant. And if conditions favor them, a week later there will be billions of them.

Still, "it couldn't hurt" to be sure there are plenty of what you need, rather than "theoretically more than zero".

>> Gardening in pots indoors, with packaged sterile 'potting soil' might benefit more from purchased mycorrhizae, as noted above by Hostajim. But usually we fertilize our potted plants.

I agree with both: sterile "soil" needs mycorhyzzae more than any real soil would. And if you're providing fertile, nutrient rich soil and watering it adequately, there is less need for root fungi (but still some, they may protect against root diseases).

Lake Stevens, WA(Zone 8a)

This all makes good sense to me and I can't think of a thing to add. I think I will go out now and fling some compost around...

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