Glyphosate

[Jerry-B-WI]

Does glyphosate go bad with age, lose its effectiveness? I mixed up some gly 3oz/gallon and sprayed some ferns a week ago, checked them today and they laughed at me. In the past when I used that same mixture from the same jug of concentrate it smoked the ferns.

 

[Foggy47]

^ I have never heard of Gly going "bad". I used to move mine to heated storage space.....but then learned that freezing did no harm. Been leaving mine in ambient temps since that time.....and never saw any deficiency on any of my herbicides over the years.

 

[T-Max]

The only thing I’ve seen on most chemicals, not Gly specifically, is to shake them before you use them if they have frozen. No mention of them going bad with time.


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[Garrett S]

As above- no concerns w age but freezing messes it up


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[Foggy47]

Hmmmm. Just did a google on freezing of some herbicides. I've been led to beleive that all were safe from freezing. Seems Gly may be a non-event.....but not so sure about others. I may bring mine into a heated storage space next year. Here is an article by a university on this issue.

Temperature Effects on Storage of Agricultural Pesticides

Fred FishelDepartment of AgronomyThe normal temperature range recommended for storing liquid pesticides is usually 40 to 100 degrees Fahrenheit. Some pesticide labels state the specific temperature range for maintaining optimal storage shelf life. Temperature extremes in the pesticide storage...

extension.missouri.edu

 

[Catscratch]

But... what about heat?

 

[Foggy47]

But... what about heat?

You got something to offer here Cat?

 

[356]

The gly we use on the farm gets very hot in the shed each summer, and below zero during the winter. I’ve not noticed any deterioration year to year.

Below is some very good info from the University of Montana:

The main concern when storing herbicides in cold conditions is that if the liquid expands upon freezing, the container holding the pesticide may crack or rupture. The simplest solution to this problem is to avoid excess pesticides that require winter storage. If over-winter storage is necessary, the following information, adapted from the 2005 North Dakota Weed Control Guide, gives the minimum storage temperature to avoid risk of reduced herbicide activity.

No storage temperature restriction: Metolachlor products, EPTC, Surpass, Achieve, Maverick. Most dry formulated herbicides in DF or WDG formulations.

Do not store below 40 degrees Fahrenheit:
Assert, Avenge, Campaign, Command, Discover, Extreme, LI-700, Nortron, Prowl, Pursuit Plus, Sonalan, trifluralin.

Do not store below 32 degrees Fahrenheit
Agri-Dex, Basagran, Far-Go EC, Flexstar, Goal, paraquat, Grazone P D, Hyvar, Kerb, Liberty/ATZ, Lorox DF, Poast, Pramitol, Progress, Puma, Pursuit, Quest, Raptor, Redeem, Reflex, Reglone, Stinger, Thistrol, Ultra Blazer, Velpar.

Do not store below 20 degrees F Fahrenheit
Fusilade DX, Plateau, Ro-Neet, Weedar 64.

Do not store below 16 degrees Fahrenheit:
Camix and Lumax.

Do not store below 10 degrees Fahrenheit:
Amitrole T, Arsenal, Curtail/M, Crossbow, Dakota, Fusion, glyphosate, Rodeo, Roundup.

Do not store below 3 degrees Fahrenheit:
Atrazine 4L, Low Vol ester, Bronate Advanced, bromoxynil, bromoxynil Atrazine, Shotgun.

When the winter is over, herbicides should always be checked before they are used. Liquid products that have become separated, crystallized or coagulated should be placed in a warm area (about 70 degrees F) for several days, during which the containers should be inverted or shaken periodically. Usually, the warm temperatures and agitation are enough to redissolve the crystals into the solvent. If the solution does not redissolve, it probably should not be used.

 

[Catscratch]

You got something to offer here Cat?

No sir. Curious what people experience. It gets hot here and sometimes I leave my stash in the shop for a day or two. Gly is mostly a mixture of salts, so heat shouldn't be a problem but ya never know what others have to offer.

 

[Foggy47]

gotta say here.....I've stored all of my herbicides in my uninsulated pole shed each winter......and never had any ill-effects.....at least to my knowledge. Been wondering about things like 24-d and clethodium, Imox, and more. Now I gotta haul the more expensive stuff home for the winter.

 

[b116757]

Glyphosate and other herbicides will often seem to have little or no effect if you’re in a drought situation and once it rains the full effect is generally seen in short order. This could be what your seeing happen with your ferns.

 

[Wild Thing]

I agree with b116757 that the drought conditions will likely hamper the effects of Gly. The plants need to be actively growing for best results.

Also, if you are using well water which contains minerals you need to treat the water with AMS (Sprayable Ammonium Sulfate) BEFORE adding the herbicide to your tank. 17#/100 gallons is recommended (1.7# per 10 gallons).



1 Solo cup of AMS weighs about a pound or so...

 

[Wild Thing]

BTW - My pole barn is well insulated but it is not heated (except for the man cave) and I have stored all of my herbicides there with no issues for many years. It will sometimes get down to the low to mid 30's if the outdoor temp gets down to 20 below or so but I have a bottled water container sitting on a shelf near the center of the barn and it never even turns to slush.

I did hear that Liberty (or generics with 24.5% Gluphosonate) should not be allowed to freeze and that appears to be correct according to the info posted above by 356. I just bought 2.5 gal of it so if I have any left over I may store it inside the man cave where it never gets even close to freezing.

 

[Jillbo]

It’s possible that if you’ve used it repeatedly over the years that the ferns have become glyphosate resistant. Maybe try another herbicide for awhile. We like tenacity for certain applications.

 

[b116757]

I do store my Milestone in a heated space but it’s water based and quite expensive so I’m uninterested in rolling the dice on it but most all other herbicides we use are stored in an un-insulated shed.”

 

[Wind Gypsy]

Dont remember if it was the triclopyr or simazine label I read last year that advised freezing is a problem but it had me pulling all of my herbicide into climate control for the winter. Good to know it's not critical for all of them.

 

[gjs4]

I had heard that freezing gly causes crystallization which not only separates aspects of it but limits its uptake. Not sure when and where I heard that.

Plants in drought go through almost a self imposed dormancy. If the plant isnt growing or actively using cellular transport, the kill will take a lot longer or struggle to take place. Based on experience a happy growing plant will croak quicker than one starved or spoiled with water, just as much as a young growing plant will die quicker than a fully grown one (with Gly application). User results may vary...