# Shelf life of glyphosate after mixing from concentrate



## vancwa (Oct 28, 2021)

I understand that glyphosate when diluted from concentrate should be used quickly (a day or two?). If left in concentrate form, it will last multiple seasons. And the pre-diluted RTU product will also last a long time. The skeptic in me says that this doesn't seem right. Why wouldn't diluted from concentrate last the same amount of time as the RTU product?

Some have hinted that diluted from concentrate loses potency over time. I've also heard stories that some water used in dilution can result in turning into a viscous fluid over time that would make it difficult to use or clog up sprayers. It's pretty easy to use distilled water if that would help.

Does anybody have knowledge or experience with this?


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## greengrass (Sep 9, 2018)

It will start to gel up into clumps in the mix. I make a new batch each year that still works throughout the year.


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## Lawnbadix (10 mo ago)

RTU sprays include preservatives.

Distilled water might help against clumping.


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## Lawn Noob (Jul 26, 2020)

I've sprayed generic glyphosate that I had mixed for over a year. It does gel a bit, but it still sprayed and killed grass just fine enough.


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## vancwa (Oct 28, 2021)

Thanks everyone. I'm always mixing up smaller quantities to avoid diluted storage but it's a pain, so I really appreciate hearing about the ability to store for longer periods of time. I probably would use it up within a month or two anyway.


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## Monocot Master (Feb 28, 2021)

I posted a related thread a while back. Adding a bit of 3-way to my mix has eliminated the issue I was having. Also, I have not experienced any notable efficacy issues after long term storage of the final gly mix in my sprayer.

https://thelawnforum.com/viewtopic.php?f=2&t=31706&start=20


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## vancwa (Oct 28, 2021)

Monocot Master said:


> I posted a related thread a while back. Adding a bit of 3-way to my mix has eliminated the issue I was having. Also, I have not experienced any notable efficacy issues after long term storage of the final gly mix in my sprayer. https://thelawnforum.com/viewtopic.php?f=2&t=31706&start=20


Interesting. Thanks for the thread! Easy to mix in a tad of 3-way to the mix.


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## BobLovesGrass (Jun 13, 2020)

"Water" means different things across the country. Heck across the neighborhood.
PH and dissolved minerals changes a lot.


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