To get rid of crab grass, apply preemergent herbicides, water the grass, reapply herbicides, overseed barren patches, keep the grass levels around 3 inches high, and add additional fertilizer in the fall. Getting rid of crab grass can be difficult, but proper care and maintenance should yield a healthy lawn.
- Apply preemergent herbicides
The quickest way to get rid of crab grass is to apply preemergent herbicides to problematic areas. Follow the manufacturer's instructions carefully. Measure the yard, and make sure the spreader is properly calibrated to deliver the right amount.
- Water the lawn
Water the grass after applying herbicides. This is necessary to activate them.
- Reapply herbicides
Some crab grass seeds germinate quicker than others. Wait a few days, then reapply the herbicide to kill surviving seedlings.
- Overseed bare areas
Crab grass tends to sprout in bare areas in the yard. Follow the directions on your grass seed package to determine proper overseeding rates.
- Keep the grass fairly high
Mowing the grass too low gives crab grass access to sunlight and reduces your lawn's vitality. Keep your lawn around 2 to 3 inches high to choke out crab grass.
- Fertilize in the fall
After autumn frost has killed crab grass, fertilize or compost the lawn. Use more than you did in the spring.