[Don Boles]

How long can a glyphosate/water solution sit in a stainless steel tank without affecting efficacy?
Never seen/heard anything on this but my SWAG is as long as it doesn't freeze.

And it still wouldn't change efficacy but it's really hard on the plumbing.

I wish labels would include this info on them, right now we are only informed of the spray mixes that are suspension disasters
but we are not informed of any changes in efficacy and why that change.
Also perhaps different quality of water may also make a difference.

 

[nig71]

Years with agitation; it will eventually lose color. I have known it to settle to the bottom of a tank before. I take it it is liquid not dry formulation?

 

[Ben Heide]

I've left it a couple weeks before, though usually only a couple hundred gallons and then agitate and top up the tank with more mix for the next job.

You're idea of recommendations would be useful, though to be honest I probably wouldn't look for it!

 

[Snipe]

How long can a glyphosate/water solution sit in a stainless steel tank without affecting efficacy?
Never seen/heard anything on this but my SWAG is as long as it doesn't freeze.

And it still wouldn't change efficacy but it's really hard on the plumbing.

I wish labels would include this info on them, right now we are only informed of the spray mixes that are suspension disasters
but we are not informed of any changes in efficacy and why that change.
Also perhaps different quality of water may also make a difference.

You need a sprayer with a smaller tank, they always seem to be empty so no issues with left over spray. I will trade ya

 

[Licensed to kill]

How long can a glyphosate/water solution sit in a stainless steel tank without affecting efficacy?

As long as you like. No time limit.

 

[Kurt]

good question , never thought a bout that .
I think it will still work 100% , cause I used to leave it in tank with desiccate and then in late fall use it again , but always top it up with new. So I would not know if it would loose any of its power.

 

[SouthernSK]

A lot will depend on the quality of water. If the water is poor with a lot of mineral I would be worried that some of the roundup will be inactivated over time.

 

[Christian A. Herrnboeck]

Water quality... that's important as stated.


Keeping the tank in shade (heat breaks down glyphosate salts)

Type of glyphosate... or rather the carrier medium. Veg oils like NuGlo will go grey and build sludge if you leave them too long. Petroleum bases like roundup and maverick are good as long as you want them to be.

 

[bent]

With a good dose of AMS I know it will last for 6 weeks.

 

[redgreen]

I had a hand pump sprayer in the shed full of round up, 1 litre of RUp ultra two in 20 litres of water that I mixed up last summer, never used it. So it froze solid (surprisingly never broke the pump sprayer or fittings) and I used it after seeding around bins and such, worked just as if I mixed it up the day I sprayed it out. A tad different then a sprayer tank and plumbing....but I think the chemical efficacy question can be answered with this test.

 

[Licensed to kill]

I had a hand pump sprayer in the shed full of round up, 1 litre of RUp ultra two in 20 litres of water that I mixed up last summer, never used it. So it froze solid (surprisingly never broke the pump sprayer or fittings) and I used it after seeding around bins and such, worked just as if I mixed it up the day I sprayed it out. A tad different then a sprayer tank and plumbing....but I think the chemical efficacy question can be answered with this test.

Similar experience to mine but mine didn't freeze and was several years old.

 

[WilgerIndustries]

I think it is just a question of agitating it to its original stored form. Like some of the guys were saying that it will get to become a sludge/concentrate at the bottom of the tank.

I'm sure the chem companies would have to have some 'extra' active ingredients in the chem, as I don't think there is such thing as a 'perfectly mixed' batch of chemical.

 

[Licensed to kill]

As long as you like. No time limit.

I stand corrected. "A large field sized sprayer with a low rate of Roundup shouldn’t set for more that a couple days before using. A small backpack sprayer with a 2% or greater solution of Roundup mixed with clean tap water could probably set for an extended period and still be used."
Roundup – Breakdown in Tap Water | Walter Reeves: The Georgia Gardener

 

[WilgerIndustries]

I stand corrected. "A large field sized sprayer with a low rate of Roundup shouldn’t set for more that a couple days before using. A small backpack sprayer with a 2% or greater solution of Roundup mixed with clean tap water could probably set for an extended period and still be used."
Roundup – Breakdown in Tap Water | Walter Reeves: The Georgia Gardener

Good article. I guess there is a little more happening behind the scenes than I thought.

 

[Ben Heide]

Keeping the tank in shade (heat breaks down glyphosate salts).

Sooo, you're saying I shouldn't have those totes sitting on the south side of my bins waiting to be used all summer?? Never thought of sunlight breaking down the AI.

 

[WilgerIndustries]

Sooo, you're saying I shouldn't have those totes sitting on the south side of my bins waiting to be used all summer?? Never thought of sunlight breaking down the AI.

Guess so. Kinda makes me a little worried as I know a few chemical distributors that have warehouses of the stuff in totes (usually in climate controlled conditions), but it might literally sit for two years before it is sold. And THEN, the farmer might sit on it for the whole summer as well.

I'm sure there are the ion exchanges and stuff when the tote is just sitting in the sun though.

Might answer some questions if guys are having heavy roundup resistance in their area (might be just a mad local supplier with old product - just kidding)

 

[Don Boles]

Best spraying conference ever!

This discussion is taking me back 22 years, the Regina Farm Progress Show put on "Applitechnica 1992"
Focused on all things spraying it provided one of the best textbooks I have ever read. Which I can't find of course.

I remember having a real interesting conversation with researcher Lawerence Townley Smith centering around water and glysophate ratios.
Now in 1992 there was only the 356 gm/L formulation and I remember Lawrence telling me if you maintain 10 gm/L active or higher results were much better.
That would be 1 liter Roundup in 35.6 liters and back in those days Monsanto still had us giving weeds a bath, not just spraying them so concentrations were significantly lower than 10 gm/L.
I NEVER spray roundup over 40 L/HA and have sprayed as low as 20 L/HA

That textbook and conversation was overall the most useful I've learned about spraying at any event!
Far and away!

 

[montana]

I have several times over the years been unable mostly do to wind sometimes rain not able to finish a load ...and of coarse just plane bad planning. If it going to set very long I close a valve or two and flush out pump and boom. I usually get my ph fairly, low so I thinks as stated above helps...I have often wondered about premixed roundup that you buy in a store in this little containers where you just pump and go no more water needed... Next time my mom gets impatient and doesn't Waite for me to mix her up a batch and she buys one of those jugs I will test the ph with my electric ph checker ..kinda curios now...also if you look at those little roundup containers they have some that have Extended control up to six weeks or something ...guaranteed if you reed the label no other ingredients ? And I do not care what unlabeled type surfactants that they do not have to list on the label I am sure when it hits the dirt you will not be killing anything that is not allready out of the ground...