Hard to kill but easy to keep out of your lawn.
Crabgrass is an annual grassy weed. It germinates in spring when the soil temperature is at least 55° for 3 to 4 consecutive days. This is one weed you do not want to discover later in the season. At that point, very possibly, nothing can be done to kill it without causing collateral damage. The only option left would be pulling it by hand. And since it may have already crowded out your desirable turf the result could be an unsightly bare spot.
The good news is, the defense has the advantage in this case. An early application of a pre-emergent herbicide is all that is needed. This should be done around the time you see the forsythia’s yellow flowers in bloom. This simple approach can effectively prevent crabgrass from showing up at all in your lawn for a whole year. This treatment is included in TML’s Lawn Fertilization Program Round #1.
Note: you do not want to aerate or seed your lawn in conjunction with this treatment.