How long does Roundup last?

[GaryM]

I'm using "real" Roundup and the answer might be different for the generic stuff.

If I mix up say 2 gallons according to the label directions and have half leftover in the sprayer, does it go bad with time? If so, how fast?

It's convenient to have it in the sprayer so I can just grab it after work and hit a few weeds here and there. Get them while they are young.

But if the mixed solution loses strength after mixing perhaps I'm wasting my time.

[Gatorboy]

It lasts for a long time -- months if not more. If it had a short shelf life, those bottles of mixed Roundup on the shelves at Home Depot would have to turn over pretty quickly.

I've had mix in my sprayer over the winter, and next spring still works like a champ. Downside is I usually have to clean out my spray tip, for it gets a bit gunked up if I don't clean out my sprayer in the fall.

[GaryM]

Thanks Gatorboy. I thought about the premixed stuff after I made the post. But then thought that they might add a stabilizer or something to the premix.

Now I have to go out and spray.

[Bird]

I've got one of those little pre-mixed squirt bottles and every time it gets empty, I just mix some more in it and keep it handy for spot spraying in flower beds or cracks in sidewalks, etc. It seem to keep just fine.

[GaryM]

I've been keeping some mixed up in my sprayer, but sometimes it seems as though it doesn't work as fast as I felt it should. So I was thinking that perhaps it lost strength after mixing.

Glad to learn it's not the case. [img]/forums/images/icons/smile.gif[/img]

[Gatorboy]

I'm sure you are aware that it takes up to 7-10 days before results can be seen.

[GaryM]

What about the TV commercials where they say 24 hours? [img]/forums/images/icons/crazy.gif[/img]

Part of the problem may be that I don't always remember when I sprayed them. I don't mark the calander. Perhaps I should do so, but I might spray several times during a week when I happen to notice some stuff growing where it's not desired. So I guess I lose track of what I sprayed and when.

[Gatorboy]

<font color="blue"> ( What about the TV commercials where they say 24 hours? ) </font color>

I think that's a different type of Round-Up. You want the 7-10 day stuff.

When I spray, I do not spray again until at least a week later -- that way I'm not spraying the same stuff twice. I figure, if I missed something, that bugger got a 1 week stay of execution. [img]/forums/images/icons/grin.gif[/img]

[Pat]

Gary, Adding a marker dye to your Roundup makes it much easier to keep track of where ou have already sprayed, especially if you are back the next day and have a "senior moment."

It doesn't really matter if you use ROUNDUP or a generic except to your pocketbook. Read the list of active ingredients. You are buying glysofate with a surfactant (detergent like stuff to break down surface tension and promote wetting.) Do the math and buy whatever gives you the most glyphosate for the least $. Some brand X stuff might not have enouigh surfactant for good wetting I suppose but I haven't found that problem yet. You can buy a jug of SurfKing or other surfactant at your handy dandy nearby ag store and mix in a little if your spray beads up on leaves and doesn't "wet" them well.

Brand loyalty to ROUNDUP is as useful as brand loyalty to Morton to buy salt to melt ice, a waste of $.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]

[MikeNC]

I haven't noticed a potency problem, but it sure seems to gum up the sprayer nozzle more when it sits longer than a couple weeks after mixing. I've had a bottle of generic concentrate for 2 years now, and it's still killing stuff.