Use of round-up
Thank you for the question. You will need to wait until the weeds are dead before you cultivate. While this seems an obvious answer, it's not that easy. Younger weeds are easier to kill than mature weeds. Annual weeds are easier to kill than perennial weeds. So, if you have all annual weeds, they will probably be dead within a week depending on the weather. Perennial weeds may take a few weeks or more to die. You will want to wait until all the weeds are dead so that you don't risk tilling live roots and runners. Chopping these up and distributing them throughout the soil with a tiller can make your weed problem even worse as each segment takes root and grows another weed.
It's important to read the complete product label because there are many different Roundup formulations and with each one comes different directions. The label is the law.
Thank you for contacting Extension.