Doing so will let more natural light in, to warm the ground, which encourages rapid growth.
Fertilizer takes time to work well.
Consequently, the sooner you can fertilize, the longer it has to work and the better the outcome. When crabgrass has been a problem in the past, you can prevent it this season, at the same time you fertilize. There are many combination fertilizers and crabgrass control products available at your local garden center. Additional recommendations and comments follow in the next section. The only way to defeat crabgrass is prevent it from sprouting, and you can do it at the same time you fertilize.