Roundup Application Temperature. Roundup contains a herbicide called glyphosate. Heavy rainfall soon after application may wash this product off of the foliage and a repeat application may be required for adequate control.
The maximum labeled roundup rate in roundup ready 2 yield soybeans is 44 ounces per acre in one application. They can be a real nightmare! Best results come from morning applications due to the long light period before darkness.
However, roundup is effective throughout the season against plants.
Roundup weedkiller is the worlds best selling herbicide, used in gardens everywhere. Unused roundup that is already diluted will remain potent for six months in storage. There is very little growth in most plants and thus very little herbicide absorption. Roundup contains a herbicide called glyphosate.