How to Use Rock Dust

A brief article about rock dust (Basalt, Azomite, Glacier). The article does not say how long it takes micro-nutrients to dissolve from the rock amendment into the soil.

Here is the article: https://www.groworganic.com/blogs/articles/how-to-use-fertilizers-rock-dust

Greensand and Kelp Meal also have nutrients and trace elements.

About a hundred years or so

The3rdMan said:

A brief article about rock dust (Basalt, Azomite, Glacier). The article does not say how long it takes micro-nutrients to dissolve from the rock amendment into the soil.

Here is the article: https://www.groworganic.com/blogs/articles/how-to-use-fertilizers-rock-dust

Greensand and Kelp Meal also have nutrients and trace elements.

Click to expand...

Because they don't really dissolve into the soil. The roots exude 'stuff' to dissolve the RD and make it available.

*I* only use Greensand and Azomite now @1cup of each/cf.

Wet

Wetdog said:

Because they don't really dissolve into the soil. The roots exude 'stuff' to dissolve the RD and make it available.

*I* only use Greensand and Azomite now @1cup of each/cf.

Wet

Click to expand...

Maybe dissolve is inaccurate. Many organic growers create their soil mix and let it homogenize over a period of time to allow some of the nutrients to leach into the soil so that they will be available to the plant..

The basalt rock dust I got from buildasoil has rocks and dust in it.

The Azomite is powdered and looks like it would break down and allow some micronutrients to leach into the soil more easily than the others. Some growers complain it has toxins in it while the FDA generally recognizes it as safe (GRAS).

I haven't seen what Glacier dust looks like.

Greensand does not look like it would break down very easily but is great amendment for soil structure.

Azomite might be the best option since it is powdery and subcool used it with great success over many years.

Unfortunately, we don't know how long it takes any of the rock dust or greensand to break down in the soil. So, I just follow other's advice.

In this non scientific article a science lady says bacteria use their gross slime layer to chemically break down rocks.

Also humic acid and other humates(?) form "bridge" to transfer minerals from clays like azomite to roots.(citation needed.)

So soil with more active microbes (tons of living bacteria) and more organic compounds (broken down organic matter and compost) will break down rock dust faster than harsh dirt.