Does herbicide have a shelf life? After mixed?

[donn12]

I just got my extra backpack sprayer and filled one up with lesco three way and water (for weeds in the grass) and the other with roundup and water . The roundup is probably 8 years old. Is it still as good as when new? Does it matter how soon I use both of these now that they are mixed?

 

[MMagis]

I'm not sure about shelf life of concentrate. I'm guessing it will work, but that's just a guess. I've accidently left some mixed over winter, and it still worked fine the following spring. But be warned, after it sits for a while it forms some sort of "snot" that will clog up your sprayer tip.

 

[westbrooklawn]

x2 on what MMagis said....

 

[beenthere]

And freezing doesn't help either.

As far as the roundup goes, I've not had a problem with shelf life in the concentrate form. Been about that long with mine, and it worked all too well this spring (a messed up lawn because I thought some mixed roundup from last year was liquid fertilizer, and even diluted it some more with 15 gal. of water and it killed the grass big time - duh!! )

 

[9973720wb19]

MMagis beat me to it! I learned the hard way...left some extra herbicide in the sprayer and it would not work because it jelled up...ended up having to rinse and clean before I could use it again. In the long run, it cost more time than just to use it all on something (like the woods) and do a quick rinse.

 

[Andrewnewy]

Yes ag chemicals do have a shelf life, don't know if it's the case in the US but over hear the ones that do have a used by date printed on them.
On the point of leaving mixed chemical in a tank, overnight would be for a worst case Scenario, as it sits in tank un- agitated it will separate and depending on the chemical it won't always blend back properly. Besides that, if you don't rinse you spray equipment properly after using it you are just doing damage to seals & diaphragms, which are often way more than the cost of dumping the left over chemical

 

[donn12]

Thanks

 

[clemsonfor]

Yes ag chemicals do have a shelf life, don't know if it's the case in the US but over hear the ones that do have a used by date printed on them.
On the point of leaving mixed chemical in a tank, overnight would be for a worst case Scenario, as it sits in tank un- agitated it will separate and depending on the chemical it won't always blend back properly. Besides that, if you don't rinse you spray equipment properly after using it you are just doing damage to seals & diaphragms, which are often way more than the cost of dumping the left over chemical

Not sure about over there but this is ILLEGAL over here. You can though use the extra Roundup in the woods like was said to kill undesirable tree species or brush, or say kill 6" of weeds along the county highway along your place etc, as long as it is a labled use. It dotn matter what is is and weather or not it truly will hurt anything the label does not say you can dump 3 gallons onto the ground, leagally you cannot do it and could be charged with a federal crime by the EPA (here in the US). Some one would have to turn you in, but you never know whos eyes are on you.

 

[Andrewnewy]

Not sure about over there but this is ILLEGAL over here. You can though use the extra Roundup in the woods like was said to kill undesirable tree species or brush, or say kill 6" of weeds along the county highway along your place etc, as long as it is a labled use. It dotn matter what is is and weather or not it truly will hurt anything the label does not say you can dump 3 gallons onto the ground, leagally you cannot do it and could be charged with a federal crime by the EPA (here in the US). Some one would have to turn you in, but you never know whos eyes are on you.

Sorry I should have specified that bit in more detail, Yes it is Illegal here to just dump bulk chemical on the ground. The common practise is to spray out any excess, at the same speed and application rate that it was mixed for. Normally along gravel driveways or anywhere else that it is safe & legal to do so.
When it comes to washing down the equipment, you MUST have a specified wash down area, capable of containing a spill of the total amount of chemical in the area, i.e. total of the tank + all chemical containers. (completely Bunded) This area has to have a drain which drains to a chemical sump, this then gets pumped out to a lime bed located in a 'Safe' area The lime bed is used to neutralise the chemical, and filter out the water.

On top of this all spray equipment must be triple rinsed, with these rinsing's dealt with via the chemical sump.
As well as al this anyone who use's chemicals (more than 1 ltr at at time) has to have a licence.
This is what the law state and people are meant to comply with.

Unfortunately this almost never happens really the only place i've seen proper chemical areas is on vineyards & commercial Orchards. Unfortunately most farmers don't realise the rules or comply with them, a lot don't even where the correct safety gear when handling chemicals.

 

[ToadHill]

I don't know how long you've had the mixed 3 way in the sprayer but I can tell you when we spot treated with 3 way a number of years ago, we left some in the sprayer over winter in a building at about 55 degrees and used it the next spring, on the business lawn, and it worked just as well as it had the past fall.