Your lawn may appear well manicured in spring, but hiding beneath those lush blades of grass is a silent invader that is just waiting for midsummer to spring on you. Crabgrass and other wide bladed grasses typically sprout in late July and are difficult to get rid of until the first frost kills them off. The best way to get rid of wide-bladed grass is to prevent the seeds from germinating with a combination of good lawn maintenance and pre-emergent herbicides.
Apply weed and feed in early spring when the azaleas and forsythia begin to bloom. This is the time that wide-bladed grass such as crabgrass begins to germinate. Weed and feed will prevent the germination of wide-bladed grass seeds, while the fertilizer in the product will nourish the established grass in your lawn.
Reapply weed and feed in 30 days as the product wears off.
Water your lawn deeply once a week with a garden hose and sprinkler. To do this, turn on the hose and allow the sprinkler to run until an inch of standing water is mixed in with the grass. This water will soak into the soil.
Set your lawn mower to mow your grass to a height of 3 inches. This will shade the roots of your grass and the soil so that weed seeds will not germinate.
Rake your lawn in September with a garden rake to cut 1/8 inch furrows into your lawn. Apply lawn seed with a broadcast spreader. Water your lawn to germinate the seeds. The furrows will allow the seeds to contact the soil. They will develop grass roots over the winter. In spring your thicker lawn will help to crowd out any crabgrass or other thick bladed grass.