# Why do humic acid app rates vary so much between products?



## ryeguy (Sep 28, 2017)

I've been considering using soluble humic powder as my humic acid source once i finish off my stash of n-ext products since it's so much cheaper. I've been looking at various humic products to see which app rate I should replicate, and it seems to vary so much:

- Humic 12 suggests a max of .23 lbs/M per year of humic 
- Natural Guard Humic Granular suggests a max of 21 lbs/M per year of humic 
- Humic DG suggests a max of 3.21 lbs/M per year of humic

All rates given above are (max allowed rate * product weight * humic acid percentage). Humic12 is a liquid so I converted it to a percentage of total weight of the jug.

Why do they vary so much? Could there be quality differences between the HA that make it need more of it? All 3 mention being derived from leonardite.


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## Miggity (Apr 25, 2018)

Different concentrations of HA and additional ingredients. Untreated humic acid (much like biochar) will rob the soil of nitrogen temporarily while it is being 'charged'. You can pre-charge HA by combining it with nitrogen and other micronutrients for better performance, but the max app rate is mainly due to nitrogen tie up concerns. 12% humic acid in water should be your final concentrated liquid, you will have difficulties above that amount.


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## ryeguy (Sep 28, 2017)

You mention different concentrations of HA, but I already accounted for that. The numbers I gave are lbs of HA, not product. Is there something more to this?

The labels of the granulars don't mention N or micronutrients. Are you saying they have some unlisted additives that allow them to have more HA in their product? Where can I read more about HA tying up nitrogen?

Regardless, I'm not understanding how that explains how .23 lbs/M and 21 lbs/M can both be effective doses of humic acid. It seems like one would have to be either ineffectively small or wastefully large.


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## Miggity (Apr 25, 2018)

> Is there something more to this?


Yes. Dry solubles (70% HA) are fully reacted and then dehydrated and eventually reconstituted by the user. Humic 12 (12% HA) is mostly reacted and kept in it's maximum concentration in it's reaction liquid but brought down in pH (Air-8 is left at it's alkaline pH, D-Thatch has molasses added, MicroGreen and Green EfFect have micros and N added). The HuMic granular product is 35% HA and does not say it is dissolvable. It does not appear to be reacted and may be in a more raw form needing much time to break down and be useful to soil and plants.

N and mircros are something that you may choose to add to your liquid HA application to reduce N tie up and increase plant uptake ability by chelating an organic molecule to metals such as iron or zinc. I was suggesting N and micros in order to increase the maximum application rates of HA applied without turf damage. Google the C:N ratios of biochar and compost, they are used in similar ways.



> It seems like one would have to be either ineffectively small or wastefully large.


I think you just hit the nail on the head. The Anderson's have funded university-based, scientific studies, but there is little scientific research to back up many of these claims. Caveat Emptor is in full force on this one, but I have been experimenting with UltraMate SG, coldwater kelp, molasses and micros. Nothing spectacular so far, but my neighbors have noticed and the domination line is a bit more pronounced.


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