Prodiamine is an effective pre-emergent herbicide for pre-emergent grass and broadleaf weed control. Prodiamine acts through inhibition of root growth by blocking plant cell division steps needed for chromosome separation and cell wall formation. Prodiamine is a pre-emergent herbicide so essentially it acts as a sort of birth control for the target weed, preventing the weed seed from growing. Prodiamine is flexible enough that it can be applied in both the spring and fall for season long crabgrass control. Prodiamine also control bluegrass, spurge, witchgrass and more, and can be used safely on St. Augustine, Bermudagrass, Fescue and other common turf grasses (see label for complete list). Prodiamine is non-staining and can be mixed and applied along with fertilizer and iron solutions.