This infamous summer annual thrives in warm, moist areas. Seeds germinate in early spring in warmer climates, later in cooler areas. As the plant grows, it branches out at the base; stems can root where they touch the soil.
In flower beds, pull crabgrass before it sets seed. To thwart crabgrass in lawns, keep the turf well fertilized and vigorous, so it will provide tough competition for weeds. Also water your lawn deeply, but infrequently; this tactic will dry out crabgrass roots, killing the weeds or at least diminishing their vigor. Solarization can control crabgrass if high temperatures are achieved.
Use corn gluten as a preemergence treatment. If chemical control is necessary, in ornamental beds only, use a postemergence herbicide control that kills grasses.