re: Round up effectiveness not up to par?

Worked fine for me just a few days ago when I used it in my vegetable garden that was about 60% fallow after pulling many plants that were done and weeds were coming in due to all the rain.

I sprayed in the early a.m. and noticed that afternoon that most of what I sprayed was already dying. After 2 days of full sun and no rain it was all brown.

Also sprayed a small strip along the side of the driveway and all the weeds in that area were also dead.