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Reading Fe-EDDHA (sequestrene) labels #875554

Asked July 01, 2024, 6:26 PM EDT

Hello, I saw the article on "Selecting which iron chelate to use" and I am wondering how to read the labels for Fe-EDDHA (Sequestrene). I would like to use Fe-EDDHA. What does it mean if it says that sequestrene is "6% chelated Fe." Is this the percent of the product that is iron by weight? For example, would adding 1 mg of a sequestrene labeled as 6% lead to 1 L solution make a 6 ppm iron solution? Also, what does it mean for sequestrene to be labeled 138 vs 330? Thanks!

Iron County Michigan

Expert Response

Hello Kaylee,


I am looking into your question and have reached out to our soil fertility specialist, and I also have a call in to a local fertilizer dealer.  I'll update you when I have some answers but wanted to let you know an answer is on the way.  If it would be easier to communicate via email rather than the Ask Extension portal, you can email me at <personal data hidden>.

Best wishes,

Eric Anderson

An Ask Extension Expert Replied July 03, 2024, 10:30 AM EDT

I reached out to reps from a couple of local chemical sales/retail dealers and neither knew anything about these products as they are typically for lawns rather than field crops.  Our field crop fertility specialist had the following insights.


From what I can tell, those two products simply use different chelates and also have differing percentages of iron. The label says 6% Fe for the 138 and 10% Fe for the 330. You would read this similar to other fertilizer labels just as one would with NPK etc. Hence for the 138 product, you would calculate out your spray volumes based on that product containing 6% Fe; just as urea is 46% N etc.

An Ask Extension Expert Replied July 10, 2024, 11:20 AM EDT

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