New Lawn Over Crabgrass in Maryland: Fall Strategy

Kill everything with glyphosate now (calm day, avoid drift). Remove dead debris, loosen topsoil. Sow 4–6 lbs grass seed/1,000 sq ft, tamp/roll for contact. Keep seedbed constantly damp until 2–3″ tall, then shift to deep weekly watering. Fertilize at seeding and late fall. Next spring by April 1, apply crabgrass preventer fertilizer (e.g., Scott’s with Halts) to dry lawn, water in. Routine: fertilize late spring, early fall, late fall; mow 2.5–3.5″; water deeply weekly.