Drive XLR8 and Ortho Weed B Gon MAX Plus Crabgrass Control are effective crabgrass killers, according to About.com. Spectracide Weed Stop for Lawns Plus Crabgrass Killer also performs well.
Drive XLR8 is a powerful, concentrated post-emergence crabgrass killer, which means that it kills the grass after it has sprouted. Most states allow consumers to purchase this product, but several only permit commercial sales.
Ortho Weed B Gon Max Plus Crabgrass Control is a ready-to-use, consumer-grade liquid herbicide. In addition to crabgrass, this product kills dandelions, clover and over 190 other weed species. Ortho Weed B Gon Max Plus Crabgrass Control is does not harm lawns when used according to the manufacturer's instructions.