Crabgrass
Crabgrass is a fast-spreading annual grassy weed that germinates from seed each spring as soil warms, then dies back completely with the first hard frost — leaving behind thousands of seeds ready to repeat the cycle the following year.
Timing Is Everything
Because crabgrass grows from seed every year, a pre-emergent herbicide applied in early spring, before soil temperatures warm enough for germination, is far more effective than trying to treat it after it's already visible. Once crabgrass has sprouted, pre-emergent products no longer help.
For an already-established patch, hand-pulling or a post-emergent herbicide labeled for crabgrass are the more realistic options.
Crabgrass typically germinates once soil temperatures reach around 55°F for several consecutive days — roughly when forsythia finishes blooming in many regions, a handy natural timing cue.
A Thick Lawn Is the Best Long-Term Fix
Crabgrass thrives in thin, bare, or stressed turf where sunlight reaches bare soil easily. Mowing at a taller height, watering deeply but infrequently, and overseeding thin patches all crowd out the open ground crabgrass seed needs to germinate.
