Crabgrass is a summer annual that can quickly invade and take over the lawn. Though many variations and species of crabgrass exist, all of these vigorous growers reproduce quickly with the assistance of seedlings. With each crabgrass plant producing more than 150,000 seeds, completely eliminating crabgrass can present a challenge. While no treatment can completely cure and eliminate crabgrass, several tips can greatly reduce its presence.
Lawns that have strong, deep root systems will easily prevent crabgrass roots from establishing. Establish a deep-rooted lawn system by irrigating the lawn deeply and infrequently. The roots of the lawn respond well to slow irrigation, which allows the water to reach deep below the surface.
Pulling the weeds as they appear will reduce the potential for weed invasions. Always remove the complete weed, including the root system, by hand. Hand-pulling helps to ensure that you remove the entire root system. Leaving even a piece of the root system behind will enable the weed to regenerate.
Chemical treatments provide effective control of weeds when applied in a timely fashion. Pre-emergent herbicides prevent the weed seedlings from germinating; apply them before the weeds begin to emerge the surface. Since weeds begin to germinate when soil temperatures reach and maintain 60 degrees Fahrenheit, the weeks following the final frost make for an ideal time to apply the pre-emergence.
Reseeding thin and bald lawn patches will also prevent weed invasions. Reseed the lawn in the early spring and throughout the growing season, as necessary. Though not required, reseeding the lawn with a seed combined with pre-emergent makes an ideal application for spring.
Air circulation and sun penetration are key to reducing the potential for weed invasions. Keep lawns free of debris to allow penetration of these well-needed requirements. Lawns require annual thatching to remove any excess debris that lies between the grass blades and the soil's surface. Aerate your lawn to provide improved oxygen flow throughout the lawn's surface. Improved circulation and sunlight penetration increase the lawn's ability to produce the nutrients it needs to grow vigorously. Vigorous grass growth, of course, is the easiest way to prevent crabgrass invasions.