How does Scotts with crabgrass preventor work?

Scott's with crabgrass preventor is a granular fertilizer and herbicide combination product. The fertilizer is coated with a pre-emergent herbicide that prevents the growth of crabgrass in an established lawn area. Timing of the application in the spring is extremely important to maximize results, two well timed applications are more effective than one application. Remember to always check labels for correct use and application rates, and always keep out of the reach of children.