Although I am no garden expert I would think it would work best in the warmer weather. As plants tend to go in a dormant mode in cold weather, they still need moisture to stay alive. But as it gets colder this need diminishes thus the likelihood of the Roundup working as well as it would in warmer weather is also diminished.
I am sure it will work, but the time for it to show results would be much longer then during the regular growing season. And adding more will do nothing other then waste the product and pollute the soil around it.
I think the answer is actually on the label, agree w/woodbridge as I've recently but some on a hill and w/the huge flux in temps I've seen no results
Sping, summer, fall and winter I've been usin a natural herbicide make od 1 gallon white vinegar and 8 drops of dishwasher detergent in a sprayer. Works like a charm and is very inexpensive.
LandlightS, that sounds like a great idea! How well does it work compared to Roundup? Will it work on any weed?
it killed poison ivy in our back yard. The acetic acid in the vinegar does the killing. The drops of dishwasher soap helps it sticks to the leaves.
Here is the link where I found the info:
In my experience, the vinegar solution works well on tender leaves but has a hard time killing mature leaves or those thickened by summer heat.
roupd up works better when it is over 65f and over.
the 2-4D formulas( such as Trimec) work better in the cooler temperatures than the round-up.
I don't think Roundup is temperature sensitive per se. The requirement is for the plant to be actively growing. It doesn't work too well on plants that are dormant.
This works well and no poison chemicals that Roundup has.
1 Gal. Vinegar
2 C. epson salts
1/4 C. Dawn Dish Soap (The blue original)
Mix and spray in the morning, after the dew has evaporated. Weeds should by gone by next day.
I would not use Round Up. It has been proven to cause cancer. Use 1 gallon vinegar, 4 tablespoons Dawn and if you want you can add Epsom salts. Lots of recipes on Pinterest. It does kill everything it touches so if you want to protect a plant, cut the bottom off a gallon plastic bottle and put it around the plant and spray away.
Roundup will kill the bees......please don't use that stuff