I would like to treat a plot that once had lawn, but I need to stop last season's weed seed from sprouting. I will be replanting grass seed. How long should I wait?
This link could offer a solution: https://www.gardeningknowhow.com/plant-problems/weeds/dallisgrass-weed.htm
If you choose a chemical, always follow package directions after reading label carefully. The product you choose will have "wait time" before reseeding in its labeling information.