I know there are folks who are enthusiastic - if not sellers of Azomite. However, upon reading the Guaranteed Analysis it is not something I’d ever use on my property. If there are others who feel otherwise I’d like to discuss it.

Can you eleborate, please?

I don’t use it in-ground, but I do add some to my potting mix. I haven’t done any randomized comparisons or anything.

Since it’s been used in livestock feed and agriculture for decades I assumed it was a safe product.

Like most things I feel it is about knowing what you need or in this case what your soil needs / lacks. For my soil I know that Azomite is not a cure all as it is low in some of the things my soil lacks, such as Magnesium, however nothing it in strikes me as particularly harmful if used in moderation, and who knows when it comes to some of those true trace items which are rarely tested in soil.

Agree with Isaac. It is good for the micro-nutrients (the nano-nutrients?). If you have a relatively un-depleted, low rainfall Western soil it is not going to be as useful as if you have a Eastern seaboard soil, leached by millennia of rain.

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Not really. What is listed on their site, the front of the bag, etc. are minerals detected by spectrometer. This does not mean they are available to plants. For that information look at the section on the back of the bag titled Guaranteed Analysis.

That’s not a good characterization of Western soils. The southwest has a problem of minerals you wish weren’t there plus only trace amounts of carbon.

My complaint is not what it lacks, but rather what it contains, especially the aluminum nitrate and the heavy metals.


I see its ORMI approved organic.

If its organic it must be good!



Maybe we should let people in on the secret that OMRI is an NGO?

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I can’t imagine it would be worth applying Azomite here in the north central Midwest, where we are blessed with soils (mostly) derived from rock flour within the last 500,000 years, and most had a nice refreshment of that rock flour component in the last 10-30,000 years from dust deposition (loess).

Without knowing how the metals leach and how things like soil pH and OM content impacts this azomite stuff, it is really hard to know whether the heavy metals are bound within the mineral structure or are subject to leaching. I wonder what the toxicity characteristic leach procedure results would be.

I suspect anyone selling something highlighting the presence of “rare earth elements” is selling snake oil. They have no known physiological function in plants, and their long-term impact on ecological and human health is rather unknown.

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I wonder if it matters. in a soil with good myc., such as it will exist under a tree, if they are not available now they will become available later, no? Lots of chemical signaling/nutrient exchange between the tree and the myc. If the tree eats its way through the Zn pool, the myc. will make more available from the unavailable Zn in the soil. If your soil is Zn deficient, you add some to make it better. I also have a friend who tries to garden in FL, in the most depleted sand you can imagine. He swears by azomite.

Azomite doesn’t contain zinc in a form available to plants.

Azomite Label.pdf (36.5 KB)

but it does not matter if it is available to mycorrhizae, and they then pass it on to plants. I appreciate that in this case azomite is just replenishing total levels of Zn.

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It’s not in a form that mycorrhizae can process either.

With some of the better mycorrhizae products bacteria are included to help convert such things as zinc into useful forms, or at least that’s what I was told. I guess unless you know what form? A test for zinc in soil is useless? So they only measure available zinc?
I myself have always counted on compost to add needed trace nutrients. I switch up where I get it too. From local to store bought. I have tried various products, but didn’t really see any benefit I could observe. I still try various products from time to time.

For a metal such as zinc to be available for uptake by mycorrhizae, bacteria, plants, humans(!) - it needs to be in an ionic compound. Examples include

  • a carbon-chemistry chelation such as found in leaf-drop, or a lignosulfate, or an amino chelation such as EDDHA Zinc
  • a non-toxic salt in aqueous solution, such as found in a wet clay mineral

If these were present in Azomite then it would be listed in the Guaranteed Analysis. Instead they list it in their “certificate of analysis” – a marketing ploy.

Azomite COA.pdf (66.7 KB)

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so which form of zinc is present in azomites? can it be made into Zn2+ by interaction with organic acids (fulvic acid etc.)?

I can’t see where azomite says what form of zinc? I did notice chlorine, and zinc chloride can be absorbed by plants. And yes a lower pH would create the ion I would think? I’m not a chemist, so I would not really know. I often hear metals are not available to plants in many cases, so it could be the case here.Such as lead and aluminum are just about everywhere.