Will 2,4-D Kill Crab Grass?

What is 2,4-D?

• The herbicide 2,4-D is a chlorinated phenoxy compound that kills broadleaf plants. It was an ingredient in Agent Orange during the Vietnam War. The compound is moderately toxic. Make sure you understand and follow all safety information on the label. Symptoms of toxic exposure include fatigue, weakness and nausea. Breathing the compound causes coughing, burning, dizziness and possibly muscle problems. Prolonged exposure or repeated exposure causes more serious problems.

Spring Application

• Apply 2,4-D in the early spring while the crabgrass is still young. Immediately after germination is best. Broadleaf herbicides, such as 2,4-D, are effective against crabgrass at this time in its life cycle. Once the crabgrass becomes established, it is immune to herbicides until it matures, later in the summer.

Late Summer

• Mature crabgrass is vulnerable to applications of 2,4-D late in the summer. Apply the herbicide in two applications a week apart.