Crabgrass is a coarse, low-growing weed that is prevalent in many regions of North America. Here in Southern California, smooth crabgrass is the most common variety. Crabgrass thrives in adverse conditions, particularly intense heat and drought. If left unchecked the plant can spread quickly, leaving unsightly patches of weeds growing in your lawn.
Because crabgrass grows fastest in unfavorable conditions, the best defense against the weed is a strong, vigorous lawn. By promoting healthy grass growth, you can give your lawn a leg-up on crabgrass and eliminate this troublesome weed.
You can start by raising your mower deck so that the grass in your lawn is able to grow to about 3-4 inches high. This will allow your lawn’s roots to grow deeper and starve budding crabgrass plants of the sunlight they need to grow.
Once again, the goal here is to promote healthy grass growth to combat the spread of crabgrass. To achieve this goal, apply about ½ an inch of water to your lawn twice a week in the cool early morning hours. Watering deeply and infrequently allows water to penetrate the soil more thoroughly, giving your lawn’s root systems the extra boost they need to combat weed invasions.
If crabgrass has already taken hold in your lawn, you can apply a pre-emergent herbicide in the spring to eliminate it before it spreads in the summer. Just be careful not to apply herbicide to fresh sod, as this can do more harm than good.