Jonathan Green’s Crabgrass Preventer plus Green-Up Lawn Fertilizer feeds the lawn for up to three full months and provides pre-emergent control of crabgrass. When applied prior to germination it controls other weeds such as goose grass, dallies grass, chickweed, henbit and oxalis. This product contains an advanced herbicide known as Dimension that provides postemergence control, meaning it will kill existing weeds, such as crabgrass, even after they germinate. Postemergence control is limited to crabgrass and is effective for up to four weeks post-germination. It will only kill the plant up to the 3-leaf stage of growth; a fully mature crabgrass plant has 7-leaves. Check that the spreader opening at the bottom of the hopper is closed. To select the proper spreader setting see the Spreader Settings section in the accordion below. Apply fertilizer around the perimeter of the lawn to establish a turning area. Then run the spreader back and forth within the area outlined by your first perimeter application. Always allow an overlap to avoid gaps in coverage.