Fertilzer combined with the pre-emergent/ early Post-emergent 'Dimension' This product provides “pre-emergence” control of crabgrass (including the large, smooth, and southern species) when applied prior to the emergence of crabgrass from the ground in established lawns and ornamental turfs. It can also provide “early post-emergence” control of crabgrass during the early stages of crabgrass growth after the crabgrass has emerged from the ground. However, it is often difficult to see the very small, early stages of crabgrass in well-established lawns and ornamental turfs. Post-emergence crabgrass control will be obtained only when this product is applied prior to the tillering of crabgrass, which generally corresponds to the time when you can first easily see the crabgrass plants in the lawn or turf. Dimension controls crabgrass prior to and up to 4 weeks after germination.