some people top dress it, i prefer to mix it in the soil myself but top dress does work. scratch it into the top inch or so of your soil. water in.
it works really good if you add it to your compost or vermicomposting process.
the microbes get to work on it fast because its so fine of a powder but its stays in your soil for some time. most of the minerals and trace elements are only needed in small amounts by the plant and microorganisms.
^ adding on that, most anything that is such a fine mesh will work faster then if it's a larger mesh. sometimes I take stuff to my coffee grinder to turn it into a dust
I like adding it in my "soil mix" also instead of top dressing, but I find no problem with top dressing anything as I try and feed only dry nutes when my plants are hungry..
Thanks for the responses so far. Researching ingredients for a soiless mix to start up in September. I'm using LCs soiless mix #2 as the base along with kelp and molasses. I'm going to feed with either guanos, or Peace of Mind Fruit & Flower 5-8-4 and high phosphorus bat guano mid to late flower. I like to use Plant Success Granular but I'm not sure if it's necessary to this mix?
I wanted to know more about azomite and if it would be worthwhile to add to the mix.
habeed doesnt your azomite already come in a fine powder. mine is much finer than a blender or coffee grinder could do.
smokeit. i will say you dont NEED azomite. but i like to have it because most soils/soil mixes lack minerals, n-p-k is covered always but the smaller things the plant needs are not always met. it has tons of minerals and trace elements which get used by the plant and the micro organisms themselves. there are other sources of rock powders, if you want to know more info google "soil remineralization" you will get more than enough info to help you make a decision. i know i did and wont look back.
quadracer, i have never seen it "burn" plants, but i have seen it cause some funky growth. which always it grows out of and when it does...BOOM, BAM lots of new growth like crazy. that is when i was testing it like a madman and growing with 40% azomite in a mix lol. plants can handle a LOT of it though. i prefer to use tablespoon or so a gallon of soil. or just forget about measuring and toss it in the composting process.
you will find its really fascinating and a key role in soil most people have no clue about.
if you have a granite rock quarry(granite type rock is recommended ) close by i know people who went and came home with enough rock powder to last a lifetime for free.