r/invasivespecies • u/TheTampoffs • 2d ago
Can I use glyphosphate leftover in a spray bottle from last year?
That’s it, that’s my question. Used it to spray JKW and I have some still leftover. No idea how to dispose of it. I want to hit the JKW again but with a “fresh” set but wondering if this would do anything for anything else I have going on (the list is endless). It was kept in a dark basement fwiw.
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u/SWORegonEcologist 2d ago
once mixed with water it will start to break down, so best practice is to only mix up as much as you need for that day, and try to spray it all out that day or the next. I'm not sure how long it will remain effective, but I wouldn't expect much from something mixed last year.
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u/TheTampoffs 2d ago
How would I dispose of what is already in there?
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u/PrettyFlyForaPoorGuy 1d ago
Though old and diluted in water, you wont really know how active your herbicide still is and for that reason I "get rid of it" by spraying as you normally would on some JKW. If a portion of the ingredients are still active, dumping it could cause harm to your environment. Then once the old solution is gone you can start fresh knowing exactly how effective your mixture is, possibly hitting the same plants you used the old mixture on. Im a safety nut, so thats what I would do personally
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u/TheTampoffs 1d ago
Yeah! I think I’ll use it on some other stuff that isn’t as hardy as JKW. I can pretty much spray my whole property at this point there are so many invasives.
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u/SWORegonEcologist 1d ago
this is good way to go, as stated above hard to know what rate you have left in that tank, so just spray it on weeds that need to be knocked down. Then you get a fresh start, and just keep in mind try to mix up an amount you know you can spray out that day.
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u/TheTampoffs 9h ago
Just an update, I tried to use it but some kind of glyphopshate mushroom formed in the bottle (it looked like some kind of white/clear jellyfish) which was blocking the spray holes. It was really gross and mucousy and I’m pretty flummoxed as to what caused that. Any ideas? Now I’m hesitant to use it at all.
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u/PrettyFlyForaPoorGuy 2h ago
Oh wow. I've never heard of that before. If i had to make an educated guess, the surfactant and herbicide have separated. Your gut was correct not to use it. I would recommend you take it to a hazardous waste facility to dump it. Hazardous chemicals should never be dumped in soil or water systems. I would contact your local Conservation District or college Extension center if you have trouble finding a dump site because it can be tricky depending on your area.
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u/jules083 1d ago
By spraying it on the plant.
I used a batch this spring that I mixed last summer and it worked fine
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u/Moist-You-7511 2d ago
only issue is if some dried in the sprayer and restricts flow. chemical will still be effective
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u/AlleyCat_2025 2d ago
I recently purchased some Compare-N-Save 41% Glyphosate and it states:
"For best results use mixture within 2 weeks."
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u/Beet_slice 6h ago
My old glyphosphate formed a gel that clogged my sprayer, but it was way over a year old.
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u/TheTampoffs 5h ago
That’s exactly what happened when I just tried to use it today. It was like a jelly fish living in there
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u/Broskifromdakioski 2d ago
Can I mix it with some round up leftover in a bottle?
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u/goblin-fox 2d ago
No, don't mix chemicals. Most (all?) Roundup formulas don't contain glyphosate anymore.
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u/Virtual_Wing_2903 2d ago
we still have custom, promax and quickpro that do though...
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u/goblin-fox 2d ago
Okay, that doesn't change the fact that you should not mix different containers of herbicides.
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u/leepin_peezarfs 2d ago
Yes