Glyphosate in cold

Does Roundup (glyphosate) work in cold weather?
I will let you know in a few days–however–if it snows a lot. Results postponed till spring.
It was about 38 degrees when I sprayed Lesco Razorburn this morning, (also contains diquat). Violets, lamium, and bluegrass.

I also sprayed a clump of violets with T-Zone as part of a test to compare different fall dates for treatment of violets. Results later.

Treatments of dandelions from about a month ago–most products worked fine–Speedzone worked better and faster.

1 – 20 of 49 Posts

ETM

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Diquat will smoke em
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foreplease

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Label says use when weeds are actively growing when weather is warm and sunny, above 60 degrees. I won’t use it when the majority of the hours in the 72 hours beginning with the time of application will be below 60 degrees. Every time I spray something I feel I could be made to explain myself later. With that in mind and the fact that I work on large public areas I am conservative. I don’t think it works, or is a good bet or policy to use it in cold weather. Unfortunately, your test is not going to give us the answer because you applied two herbicides together.

Former Michigan PABL

FdLLawnMan

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Label says use when weeds are actively growing when weather is warm and sunny, above 60 degrees. I won’t use it when the majority of the hours in the 72 hours beginning with the time of application will be below 60 degrees. Every time I spray something I feel I could be made to explain myself later. With that in mind and the fact that I work on large public areas I am conservative. I don’t think it works, or is a good bet or policy to use it in cold weather. Unfortunately, your test is not going to give us the answer because you applied two herbicides together.

If I did this I would never finish my season. I spray weeds until the soil temp is 40 degrees with excellent results. The weeds will probably be there until the snow flies but they will be gone next spring and that is what I and my customers care about.

Mike I
Mike’s Total Lawn Care

foreplease

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If you are talking about broadleaf weed control with selective herbicides I agree with you. Topic is gly in cold weather, which I do not believe in.
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Former Michigan PABL

FdLLawnMan

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Oops, sorry, my bad. I realize the mode of action is entirely different then most herbicides I wonder what would happen. Riggles test will be interesting but will have to wait until next spring to see results.

Mike I
Mike’s Total Lawn Care

easy-lift guy

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How can the results of testing a product be interesting when the manufacturer has already stated for best results on their own label?. Could anyone expect any different results other than the results by the manufacturer. Incredible.
easy-lift guy

foreplease

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Oops, sorry, my bad. I realize the mode of action is entirely different then most herbicides I wonder what would happen. Riggles test will be interesting but will have to wait until next spring to see results.

It’s cool, Mike. No big deal.
Former Michigan PABL

RigglePLC

Discussion Starter · #9 · Dec 11, 2015

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After five days with warmer than usual temperatures for Michigan in December, (its 52 at the moment), there is not much effect from the Razorburn spray (glyphosate, diquat).
There is some effect on chickweed.
I will check it again in the next few days.

upidstay

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Plants die as fast as they grow. If they’re dormant or semi-dormant, you probably wont see any results until next year. The only thing you’ll get quick kill is with scythe or other acid type product.

foreplease

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Did you spray any grass or are these isolated weeds in landscaping, concrete, etc.?
Former Michigan PABL

RigglePLC

Discussion Starter · #12 · Dec 12, 2015

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I treated mostly isolated weeds–except–one spot that was in grass. Chickweed in the grass spot was damaged. Grass not injured so far.

There is not much point in spraying annuals–they have been killed by frost. Of course, violets, dandelions and some perennials do not lose their leaves. Likewise not much point in spraying trees, bushes or poison ivy–if there are no leaves. But maybe I am wrong. What would happen if I sprayed some (leafless) poison ivy with glyphosate? What about dormant (leafless) poison ivy with Speedzone? Well. maybe I can try it tomorrow. That is if I can identify it, and mark it for checking ivy in spring, without infesting myself.

RigglePLC

Discussion Starter · #13 · Dec 14, 2015

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I sprayed Nufarm "Razorburn" which contains glyphosate and diquat during cold weather, 38 F. The intent was to estimate how effective it would be in cold weather.
After 5 days, the weather got warmer, up to a record temperature of 61 degrees F.

Violets showed almost no sign of herbicide effectiveness.

The test weed, motherwort appeared to be dying; the leaves looked limp and were a dull green color. Untreated motherwort looked healthy.

Bluegrass showed no visible sign of injury.
Chickweed was dead or dying in the turf treated area.

Lamium (deadnettle) showed almost no signs of injury, (not pictured).

4

B-Easy

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Any glyphosate label will state that it is a postemergent systemic herbicide. This means (and please tell me if I’m wrong) that the target plant needs to be growing in order for the herbicide to be effective. In addition, since glyohosate has little residual activity beyond 24 hours I don’t think it can be applied as an effective herbicide during cooler winter temps.

JoJac’s Turf & Tree
Serving the greater Wichita Kansas area for 35 years?

easy-lift guy

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Any glyphosate label will state that it is a postemergent systemic herbicide. This means (and please tell me if I’m wrong) that the target plant needs to be growing in order for the herbicide to be effective. In addition, since glyohosate has little residual activity beyond 24 hours I don’t think it can be applied as an effective herbicide during cooler winter temps.

You are correct. The OP makes post like this often. Just something to do until the snow and ice melt away and than something can actually be sprayed.
east-lift guy
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RigglePLC

Discussion Starter · #16 · Dec 17, 2015

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Good question–if the Kentucky bluegrass is dormant–can Roundup be used to kill winter annuals like chickweed and veronica?
I think not.

True–weed experiments are more challenging during the winter. I am probably the only one growing dandelion seedlings. I am sure there will be a future experiment, right? New dandelions–they are really small at first. I also have crabgrass and goosegrass seeds–but they do not do well in my house, as the temperatures are a bit cool for them.

I sprayed poison ivy with Roundup and two additional types of herbicide last week when it was 38 F –results later–probably much later.

easy-lift guy

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Good question–if the Kentucky bluegrass is dormant–can Roundup be used to kill winter annuals like chickweed and veronica?
I think not.

True–weed experiments are more challenging during the winter. I am probably the only one growing dandelion seedlings. I am sure there will be a future experiment, right? New dandelions–they are really small at first. I also have crabgrass and goosegrass seeds–but they do not do well in my house, as the temperatures are a bit cool for them.

I sprayed poison ivy with Roundup and two additional types of herbicide last week when it was 38 F –results later–probably much later.

I think its going to be a really long cold winter in Michigan.
" I sprayed poison ivy with Roundup"?. Maybe you sprayed round-up on poison ivy. Absolutely Incredible!
easy-lift guy

Ijustwantausername

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Good question–if the Kentucky bluegrass is dormant–can Roundup be used to kill winter annuals like chickweed and veronica?
I think not.

True–weed experiments are more challenging during the winter. I am probably the only one growing dandelion seedlings. I am sure there will be a future experiment, right? New dandelions–they are really small at first. I also have crabgrass and goosegrass seeds–but they do not do well in my house, as the temperatures are a bit cool for them.

I sprayed poison ivy with Roundup and two additional types of herbicide last week when it was 38 F –results later–probably much later.

I emptied out my roundup backpack on my gravel the other day. Had quikpro in it. I sprayed kentucy blue trying to emerge. It was yellow in a day or two with 40-50 lows at night. I did use a sticker. I can’t get over how quick the burn down is with quikpro.

ted putnam

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I use Ranger Pro(got a helluva deal on it)

The label states that it can be sprayed on dormant Bermuda to control winter annuals and Fescue clumps at rates between 8 and 64 oz/acre. I’ve used it for this at closer to high rate with excellent control of both.

Dormant Bermuda and winter annuals are around in cold weather. It does work. albeit slower maybe depending on temps

"Opportunity is missed by most because it is dressed in overalls and looks like work"- Thomas Edison, businessman/inventor

Proverbs 27:17
"As iron sharpens iron, so one person sharpens another"

RigglePLC

Discussion Starter · #20 · Dec 18, 2015 (Edited)

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I can only read part of what you wrote Ted, because the ads blocked the text. Are you listening Moose River?

Is glyphosate effective in cold weather?

I treated violets and mother wort weed on December 7, 2015. The temperature was 36.8 at the nearest ag weather station
(Walker, about 10 miles away). I applied Nufarm Razorburn, ( 41 percent glyphosate, 2.1 percent diquat),
similar to Quickpro. The high temperatures for the next 10 days averaged 47.2, but one day hit a record high of 60.6.

The results were a bit slow, (untreated in the top photo), but the mother wort weed leaves collapsed
and appeared to be nearly dead after 9 days.
On wild violets the the herbicide was not as effective, but the leaves were distinctly damaged.

The results were similar on bluegrass, chickweed, and Lamium. I can show the photos later.