Glyphosate (roundup) shelf life

[RedHawkRidge]

Working at controlling invasive plants, eg, garlic mustard, honeysuckle, etc. by spraying with glyphosate.  I buy it in 2-12 gal jugs, which is 41% concentration.  I work at it in spring and fall.  Using a 4% mix, the jugs might last more than 2 years.
So, does the 41% glyph. retain it's potency over a length of time -- how much?
Does the mixed solution (maybe 4%) retain its potency for any length of time?
thanks for any advice.
jim

[fishpharmer]

2 years according to this...
http://www.monsanto.com/products/Documents/MSDS-Labels/roundup_pro_concentrate_msds.pdf

[beenthere]

I've been working out of a 2½ gal jug of Roundup for at least 15 years now, and am not finding it any less effective.
If I were to guess, I'd say more effective killing things.  ;D

And I don't leave a mixed solution over the winter any more, as I grabbed it thinking it was lawn fertilizer and diluted about a gallon of mix with 30 gal of water... took about 3-5 days to kill the grass in the lawn. And the concentration had to have been pretty low.

[Deese]

Don't let it freeze and it should last for years...
I personallly wouldn't consider using a mixed solution that has been sitting around for a while, as it breaks down over time...

[Trahlin]

No problem with age or freezing.  We have 250 gallon totes that are bought in the fall and stored in an unheated shed all winter (Nebraska).  Have never had any issues.

We do try to keep it out of direct sunlight.

[Alcranb]

We buy it by the 55gal. Drums and have never had any problems with storage or potency and like Trahlin we store it in an unheated shed. Btw we ad about 4 oz. of a soluble fertilizer like Peter's 20-20-20 to 5 gallons of mix. We find we get a better kill than going straight mix.

[Sonofman]

I had some unmixed that my brother bought in the late 70's. I used the last of it about 5 years ago. Always stored in an unheated area. I could not tell any decrease in effectiveness. Sometimes the 'shelf life' of a product is for the benefit of the manufacturer.

[mesquite buckeye]

When mixed with alkaline water, like most well water, roundup degrades in a couple of days. Sitting in the bottle or mixed with distilled water, indefinite shelf life. Don't know if there are roundup eating organisms. Probably, but they have to find it first.

[beenthere]

When mixed with alkaline water, like most well water, roundup degrades in a couple of days. Sitting in the bottle or mixed with distilled water, indefinite shelf life. Don't know if there are roundup eating organisms. Probably, but they have to find it first.

I only wish that were true.
If it were, I wouldn't have lost so much lawn grass when I erred adding a gallon of year-old mixed solution of round-up and well water to 30 gallons of well water (thinking the solution was liquid lawn fertilizer). 
Had considerable potency being diluted that much and setting mixed that long.
So can't go along with the "couple days" degrade.  Wish I could go back and wish it were true.

[mesquite buckeye]

Don't know about your water. Out here you can tell the difference when the weeds only get sick instead of dying.  :-\

[ely]

i cleaned out an old spray tank that had 5 galsn of old mix in it. the old boss said it was no good. i noticed it was slick and slimely and had clumps of snot like stuff in it.
naturallly i strained it though a piece of house screen before putting it in my pump up sprayer. it was over two years old and it still killed like it was designed.

[jd_odell]

Mix it with a surfactant (diesel @ a 5% mix rate) and it will stick better and be "hotter".  If you don't want to use diesel, then you can use liquid detergent or pick up a surfactant at your local TSC.  Just don't make it so hot you burn the leaves off before the leaf absorbs the herbicide.  Roundup kills the roots, but it has to make it there to do so.

[Gary_C]

Glyphosate is very similiar to ordinary table salt. In fact you could drink it and you would get about as sick as you would if you drank a concentrated salt solution. I've heard that some Monsanto salesmen have even drank a small amount at sales meetings as a demonstration of the non toxic claims. If you read the MSDS you will see there is very little known toxicity.

As far as shelf life, you could expect it to degrade over time about as much as a heavy salt solution. The only degrade you could get would be if the solution was at maximum concentration, you could get some of the primary ingredient that would settle out if there was any evaporation of the water it is mixed with.

The exception to that is if the glyphosate was in contact with galvanized metal or uncoated steel it will react somewhat and produce hydrogen.

[RefHawk]

Glyphosate remains stable for several years. It is amber colored and as long as there is no salt like sediment in the bottom of the jug, it should be fine.

To control invasive plants like vines, briars, and small woody trees/plants, triclopry (active ingredient) works great. It is better in my opinion than glyphosate since glyphosate often breaks down in vines and woody plants before it is translocated to the roots. There are many trade names of triclppry on the market such as Garlon, Remedy, Element, Triclopyr etc.

Another good option is Crossbow. It is a combination of triclopyr and 2,4-D.

Adding diesel fuel as a surfactant also helps with control. If you don't want to put diesel in your sprayer, then us a good quality 80/20 surfactant or crop oil.

All of the aforementioned products can usually be obtained from any farm supply dealership. Hope this helps!