# Iron questions



## john5246 (Jul 21, 2019)

San said:


> TheZMan said:
> 
> 
> > I got a bag off Amazon from the link in the beginning. It's greenway biotech. The bag says Ferrous Sulfate. It doesn't say Hepatahydrate. Same thing or no? Seller advertised as Hepatahydrate.
> ...


Are you a chemist? Thoughts on this? Is it worth it to put down the iron in that form, and how does heptahydrate compare to EDTA, just using citric acid powder yourself, or any of these other ways to chelate the iron. 


"_There are four commonly used chelates: citric acid, EDTA (Ethylenediaminetetraacetic acid), DTPA (Diethylenetriaminepentaacetic acid) and EDDHA (Ethylenediamine di(o-hydroxyphenylacetic acid)). According to data presented by Norvel (Equilibria of Metal Chelates in Soil Solution, in Micronutrients in Agriculture, Soil Science of America, 1972) citric acid does not strongly bond with iron and is not effective at pHs above 6.0. EDTA strongly holds iron in solution up to pH 6.0, but by pH 6.5, almost one-half the iron is precipitated, and by pH 7.0, almost none of the iron is available to plants.DTPA is an excellent iron source up to media pH 7.0; however, 60 percent of the iron is precipitated and unavailable by pH 8.0. EDDHA is the strongest chelate of any of the commonly used materials and maintains iron availability to plants past pH 9.0. These chelates are ranked in the same order of effectiveness by Drs. Bill Argo and Paul Fisher in Understanding pH Management, Meister Publications._"


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## San (Jun 21, 2021)

john5246 said:


> San said:
> 
> 
> > TheZMan said:
> ...


I'm no expert, but I've done some research on the topic.

That chart is one for Turf Truth, leading with some directional correct facts and then ending with totally BS marketing statements. While EDDHA does indeed form stable complexes at 9.5pH, the reason it's so effective is because for FE it does this effectively from around 2pH and up to around 10pH. However their cheap Sodium Glucoheptonate only works as a chelator somewhere between 9pH and 14pH. At that level I think you'd have bigger problems to grow grass.

The citric acid will work as a chelator up to about 6pH

Whether it's worth it, depends on a couple of things, first how frequent you are looking to apply it.

Though I read a study that showed that chelated iron has beneficial effects when applied foliar over just iron, as it help to penetrate the wax layer. But this wasn't for grass, so I'm not sure how much difference that makes, or with different chelators versus just citric acid.

Chelated iron is to keep the iron plant available in the soil. 
However if you are willing to do frequent foliar applications, your grass doesn't have to depend on soil available iron.
In general foliar applications for iron seem to be more effective regardless.

Now if you want to spray less, and so you're just spraying to also get the iron into the soil, then the next question would be what your soil pH is. If you have acidic soil enough soil regular iron (with some citric acid) will still work. If you have a higher pH and you want to get iron available in the soil, then I would look to use a chelated iron. That picture is pretty accurate for the chelators vs pH ranges, if you ignore their Sodium Glucoheptonate marketing trick.

The last benefit of using a chelated iron is that as it's chelated and therefore not (less)oxidizing, you won't get (as much of) the rust stains, if you spill it on concrete.

Hope that helps.


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## Jconnelly6b (Mar 4, 2018)

@San one of the more concise and helpful responses I've seen on here. Bravo and thank you.


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## JERSEY (Sep 9, 2018)

Just experiment.
Under 80f!!!!
Go light at first!! Depends on your soil
I Love it.


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## 440mag (Jan 29, 2018)

JERSEY said:


> Just experiment.
> Under 80f!!!!
> Go light at first!! Depends on your soil
> I Love it.


Schuh-moken!!!!!!! :thumbup:


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