How to Control Crabgrass in Bermuda

Weeding your lawn by hand is also an option to eliminate crabgrass.

As the warm-season Bermuda grass develops in spring and summer, it faces competition from perennial and annual weeds that also thrive in the same toasty conditions. Crabgrass, an annual grassy weed, is one such invasive plant that takes over your lawn unless the grass is vigorous enough to overpower it. For this reason, give Bermuda grass the care it needs to remain strong against weeds. If the problem is severe, you also have two classes of herbicides as options.

Things You'll Need

• Lawn mower
• 1 inch water as needed
• 1 lb. nitrogen per 1,000 square feet, divided
• Pre-emergence herbicide
• Post-emergence herbicide

Instructions

1. Cut your Bermuda grass lawn to its maximum recommended height of 2 ½ inches to block light from reaching the crabgrass seeds, which depend on the sun for spring germination.

2. Irrigate established Bermuda grass when its blades wilt. Apply 1 inch of water at that time in one single session to reach 4 inches under the surface. This practice is unfavorable to crabgrass, which thrives when irrigation is frequent and superficial.

3. Fortify your Bermuda grass lawn with ½ lb. of nitrogen per 1,000 square feet in May and again in July. Irrigate the grass after you finish to water the fertilizer in. Reduce the amount of nitrogen by one-fourth if you leave your grass clippings on the lawn after mowing it.

4. Control crabgrass with a pre-emergence herbicide applied to cover the entire lawn area after it becomes green in spring, but before the weed seeds germinate. Contact your extension office or a local nursery to get a date estimate for your region. Use a formula containing benefin or a blend of benefin and trifluralin. Colorado State University Extension also rates prodiamine and pendimethalin as excellent pre-emergence herbicides against crabgrass. Apply the chemical following the manufacturer's instructions for the brand you selected.

5. Spray a post-emergence herbicide while crabgrass is still young in late spring to early summer. Use a product made of the chemicals MSMA or DSMA, applying it directly to the weed according to the manufacturer's directions. Repeat the treatment five to 10 days later.

References

• University of Illinois Extension--Lawn Talk: Managing Crabgrass in Home Lawns
• University of Arkansas Cooperative Extension Service: Lawn Care Calendar--Bermudagrass
• Colorado State University Extension: Lawn Care
• Colorado State University Extension: Control of Annual Grassy Weeds in Lawns
• The University of Georgia Cooperative Extension: Crabgrass: A Weed Problem in Many Lawns