The most effective weed control is a healthy and dense lawn. A pre-emergent selective granular is applied to prevent crab grass seed germination. However, if weeds present themselves, a post-emergent herbicide will be applied to eliminate weeds after they have germinated. The post-emergent herbicide is a selective post emergent herbicide that targets only weeds and not the turf grass plant. Typically, spot treatments will be utilized to control weed growth.