Beverly Adams, ANR Program Assistant, UGA Extension Forsyth County

Spring green-up is right around the corner. Following these practices will help maximize turfgrass and minimize weeds. There are three primary methods of weed control: cultural, mechanical, and chemical. To manage weeds consistently, we need to use all three.

Cultural control. This is the first line of defense against weeds. Through cultural practices, we promote vigorous turfgrass growth and development. A thick, healthy stand of turfgrass helps to smother weeds.

Cultural controls include:

  • Selecting appropriate plant species for the planting environment;
  • Appropriate and timely watering;
  • Managing soil health and fertility. Don’t guess, soil test!
  • Mowing with appropriate frequency to maintain optimal turfgrass height;
  • Timely core aeration; and
  • Dethatching as needed.

Mechanical control. Mechanical weed removal and prevention are our next tools. Hand-pulling a strange or new weed when it first appears will help prevent the spread of that weed. Frequent mowing to remove weed flowers also keeps them from making seeds for next year. Weed-blocking fabric under the mulch of lawn-bordering beds creates a barrier between weed seedlings and sunlight. Fences help keep pets off lawns to reduce lawn thinning caused by stress, urine, digging, and other damage.

Weeds growing up in a mulch bed.
Hand-pulling annual lawn weeds such as hairy bittercress (Cardamine hirsute) before they flower reduces weed-seed banking in the soil. This Photo is licensed under CC BY-NC-ND.

Chemical control. Herbicides are the last method in your weed management toolbox. In lawns, we use preemergence herbicides to prevent or minimize annual weeds, and postemergence herbicides to kill actively growing weeds.

In planning your weed control program, three things are very important:

  • Weed identification
  • Turfgrass species in your lawn
  • Timing of herbicide application

Mid-February to Mid-March is the time to apply preemergence herbicides to lawns to prevent germination of lingering warm season weed seeds in the soil. Not every herbicide, however, is safe to use on every type of turfgrass. The product label is the best reference for safe and effective use of any herbicide. Always read the label prior to use of any herbicide. And remember, the use of herbicides without following good cultural practices will not result in a high quality, weed free lawn.

While there are many product choices for postemergence weed control, each product controls only the weeds listed on the label. Most herbicides work best on young weeds less than 2-inches high. Spot spray broadleaf plants like chickweed, henbit, and wild violets early in the day when temperatures are between 65˚F and 80˚F. Use a foam or large droplet setting to prevent drift to non-target plants and resist spraying herbicides on windy days. Before application, make sure the active ingredients in the product are safe to use on the type of lawn you have. Triclopyr, for example, offers some control of wild violets, but it will damage bermudagrass, centipedegrass, and St. Augustinegrass lawns.

For more tips on cultural controls and herbicides, see the Georgia Pest Management Handbook, 2020 Home & Garden Edition. Also check out our UGA Lawn Care Calendars for easy-to-follow management guidelines for the common turfgrasses in North Georgia.  

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