Please, consider in the future using vinegar instead of roundup. The result will be exactly the same. If you need a proof that vinegar was a weed terminator, then look at the pictures below. One was taken in the afternoon, and the second the next day after Kevin sprayed them with straight-from-the-bottle, store-brand white vinegar.
Adding a cup of salt to the gallon of white vinegar will not only kill the weeds, it will keep them from coming back, too. Only use where you never want to grow anything ever again, though. The results are not temporary. I only add salt when I use it on sidewalk cracks and my gravel driveway.
I use vinegar and bi-carb for ant as wells weeds