Round up efffectiveness if old

Dave from MN · May 6, 2009

I have a couple containers of roundup left from the "08 and "07. I plan to use it around the tree lines we established last year. Will it be as effective o do I need to increase the amount I use? It was kept outside, dont know if the stuff freezes or not. Thanks in advance.

2t2@IA · May 6, 2009

I cannot speak with authority, only personal experience. I have used "old" Roundup at the same rate as "new" with the same results. I have even used some in a knapsack sprayer that was mixed and left over the winter with good results.

Anonymous-0 · May 6, 2009

Dave I've used round up thats been out in the sheds for couple years seems to work just fine.

rgvtx · May 6, 2009

I have used aged RU with the same results as new, never been a problem. BUT, I don't know about if it froze if that has an effect. Somehow I would think it would have an effect. Maybe you can contact Monsanto and ask?

jack harmon · May 6, 2009

Ive used it even older with no problems.what Ive heard is that the ingredients separate over time,so make sure you shake it well before you use it.

Mike (WA) · May 6, 2009

I only use about a hand sprayer full of mix each year, for along the driveway, etc. Just finished a gallon that I know was at least 25 years old (and maybe closer to 30- when did that stuff first come out?) - and it worked as well at the end as it had at the beginning. Its been in unheated shop(s) all its life, and has been down to zero degrees on several occasions.

david - or · May 6, 2009

Here's what a University of Florida site says about Roundup storage:

"Store above 10° F to keep product from crystallizing. Crystals will settle to the bottom. If allowed to crystallize, place in a warm room 68° F for several days to allow crystals to redissolve, then shake well before using."

GordoSD · May 6, 2009

Dave, using RU around trees is REAL RISKY business. Make sure you are always downwind with a little breeze blowing Never spray on a calm day. Use larger nozzles and go down with the sprayer to minimize drift. Use an olfactant.

Gordo

Anonymous-0 · May 6, 2009

Rinse out an old one gallon plastic oil jug and cut the top off leaving a rectangle container. Next make a hole in the bottom of it to put your wand in it, take the nozzle off of the wand so your hole can be smaller and push it through then put nozzle back on. You now have a hood for your sprayer that you can use on windy days and you can spray close.

brian(MN) · May 6, 2009

I have used 1 and 2 year old roundup that was kept outside in a shed with no problem, don't worry about it.
However, I do worry about your spraying around trees, just a little bit of spray driff will kill or injure a tree.
Brian(MN)

Jeff B. · May 6, 2009

Roundup is good stuff, but you have to be careful. I've killed things I didn't want to kill and not killed some things I was spraying for. For best results, use it in the late evening after a hot day. The wind has died down so there's no spray drift, and all the weeds are all opened up waiting for a drink of dew. You hit 'em with a shot of that stuff then and they soak it up like it was candy. a week later, they're guaranteed to be toast.

john d · May 6, 2009

Good idea. I did nearly the same thing with plastic funnel.

Rick Kr · May 7, 2009

Gordo,
Can you explain the "never spray on a calm day"?.
I use to notice some drift when running fine nozzles.

With larger droplets you should get the RU down and on the ground regardless.

I spray roundup directly on conifers in the fall, and deciduous throughout the summer with no ill effects.

I run big nozzles, low to the ground.

Rick

paul · May 7, 2009

Calm days often are a temperature inversion situation here in MN.

This makes the spray drift rise up into the sky, & float around like a low cloud.

Not a good thing.

A gentle breeze you know which direction the drift will go, and allow for it.

The breeze will mix the air, & disperse the drift rather than it staying together in a cloud.

As to old roundup, it can 'freeze' - it doesn't actually freeze. Won't harm the chemical, but the heavier salts might settle to the bottom of the container. It's been suggested you put the old containers in the back of a pickup & drive to town & back - or otherwise shake them up some. Will be good as fresh.

--->Paul

Rick Kr · May 7, 2009

Paul,

I figured Gordo was eluding to inversion. At my place, it is a very rare day that it is actally calm.

On those days, I have noticed some drift. I am usually looking for the days where it is calm enough to spray. Under 5mph.

Now running large nozzles close to the ground, things seem to work out well.

Rick

Bill in NorthCentral PA · May 7, 2009

I spray around thousands of trees each year with a hand sprayer. Use a flat fan tip, which allows for much greater control and watch the spray pattern, not the spray. I avoid very windy days. If you're talking decidious trees, even a little on the bark won't kill them.

Bill

Round up efffectiveness if old

Dave from MN

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2t2@IA

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Anonymous-0

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rgvtx

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jack harmon

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Mike (WA)

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david - or

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Anonymous-0

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