Watch this video from This Old House to learn how to remove crabgrass.
1 Adjust cutting depth of lawnmower to lowest setting and mow lawn; use bag to collect and discard all clippings.
2 Scrape the soil of all vegetation using a straight-edge shovel. 3 Use power rake to cut grooves into soil.
4 Spread ½-inch-deep layer of compost over soil; smooth with garden rake.
5 Apply starter fertilizer to compost using a drop spreader.
6 Use drop spreader to dispense grass seed onto compost.
7 Gently work grass seed into the compost with a plastic rake turned upside down.
8 Water the area lightly once or twice a day.
9 Next spring apply pre-emergent crabgrass control to the new lawn using drop spreader.
10 If some crabgrass returns, pull out individual plants by hand.
11 For larger lawns, use a pump sprayer to apply a post-emergent
crabgrass control directly to the weeds.