Crabgrass is an invasive weed that grows well in lawns that are lightly watered, underfertilized and relatively sunny. Preventing crabgrass with pre-emergent herbicides requires good timing. Applied too early, pre-emergents will be washed away, and applied too late, they are completely ineffective. Once crabgrass has taken root, nonchemical methods are the best means of getting it under control. Seven simple steps will help you create and maintain a crabgrass-free lawn.
Step 1: Keep the grass mowed to a height above 2 1/2 inches and fertilize more heavily in the fall rather than the spring. A thick, luscious lawn is the best defense against crabgrass.
Step 2: Water the lawn less frequently, and when you do water it, allow the water to seep deep down to the roots of the grass. Crabgrass is a shallow weed that needs an abundance of water at frequent intervals. Allowing the top of the soil to dry out while providing adequate moisture for the lawn’s root system will discourage the growth and spread of crabgrass.
Step 3: Hand-pull crabgrass as soon as you see it, before it has time to re-seed itself. Water the lawn heavily before weeding to make it easier to pull the crabgrass out, roots and all.
Step 4: Apply mulch or compost to areas where crabgrass has been removed. Covering the existing soil will keep sunlight from reaching any remaining crabgrass roots or seed.
Step 5: Overseed in the fall and if necessary, apply pre-emergent in the spring.
Step 6: Spread or spray pre-emergent after the forsythia bushes have stopped blooming, but before the lilac bushes bloom. Water the lawn immediately after applying pre-emergent to activate the herbicide.
Step 7: Do not aerate or de-thatch the lawn after applying pre-emergent. Disturbing the soil in any way will compromise the herbicide’s effectiveness.
Maintaining a thick and healthy lawn is the best way to prevent crabgrass. Follow a regular mowing, watering and fertilizing schedule and eventually, crabgrass will be eliminated from the yard entirely. Meanwhile, if you take time to smell the roses, bend over and pull out a little crabgrass along the way.