Disclaimer: Proprietary Grasses such as Zoysia’s will always develop various weeds, due to their slow metabolism rates, which makes for all of their good qualities. Nutsedge / Nutgrass is a very common weed also. Image or Imagine is very effective at controlling it, usually take a few applications. For other broadleaf weeds, it is necessary to apply an herbicide that is safe for that particular turf. With the Zoysia's and Bermuda grasses, weeds are prevalent. Always follows directions on the container, more isn't better. Round Up or Finale doesn't affect Nutsedge at all for instance. Spot treatments are best, unless there is a major infestation. Birds / Rain & Maintenance companies that do not wash off their equipment from one job to the next, tend to help to spread the contamination. Of course when we apply our soil amendments on projects that we install, it makes for a great growing medium for everything. Weeds do not come in the new Sod; the Farms go to great lengths to avoid that from happening. We are not responsible for weeds that come up in the new turf. Our grasses are delivered weed free. It is best to find a company that can treat your lawn or simply educate yourself on what to apply and when.