Fertilome Weed Out with Crabgrass Killer previously known as Fertilome Weed Out with Q is a proven solution containing three active ingredients (2, 4-D, Quinclorac, and Dicamba) that target and kill crabgrass and other weeds in your lawn. Fertilome Weed Out can be used safely on cool season and warm season lawns listed on the label when following label directions. Fertilome Weed Out acts by penetrating the weed leaves and then travels through the entire plant killing it as it goes.