Roundup Application Temperature. A warm, sunny day is best, when the weather is dry. When properly mixed with water it can kill many varieties of plants, including grasses.
Since glyphosate (roundup) is a post emergent (after the weed is growing) herbicide, the minimum temperature is related to the weed being controlled. Gardeners can apply herbicides like roundup when the air temperature remains between 60 degrees and 85 degrees. They can be a real nightmare!
The chemical kills the roots, too, so it won't come back (except for a few weeks noted on the label.)
As long as it's reasonably warm, i don't think temperature matters. Apply roundup anytime weeds are growing. I also spot treat and it's the leaves you need to spray well. Tall fescue was sprayed with roundup®, roundup pro®, roundup prodry®, and an experimental roundup® formulation;
