Grass burrs and goat heads are annual weeds that appear in the landscape when the soil warms in the spring, especially where the soil is poor. In late summer, the plants produce spiny seed heads so hard and sharp they can penetrate shoes and tires. This presents a problem for many gardeners, especially those with children and pets. While the best solution for avoiding problems with grass burrs and goat heads is a lawn with healthy turf grass that competes with annual weeds, there are other options for managing grass burrs and goat heads.
Things You'll Need
Purchase a pre-emergent lawn herbicide that is listed for controlling grass burrs and goat heads. The best way to find out what pre-emergent herbicides are currently approved for control of grass burrs and goat heads is to contact your local county agricultural extension office. This office has not only a list of approved herbicides, but also the correct dates to apply them.
Apply the first application of pre-emergent in the spring when the soil temperature reaches 52 degrees Fahrenheit. Take the soil temperature by inserting a soil thermometer into the soil and reading the temperature 3 to 4 inches deep. The pre-emergent herbicide prevents weed seeds from germinating for six weeks.
Repeat the application of pre-emergent herbicide every six weeks until six weeks before the average first frost date, to prevent new grass burr and goat head seeds from germinating.
Dig out existing plants with a sharp shovel or apply a post-emergent herbicide. Applying a contact herbicide such as glyphosate kills surrounding vegetation and leaves bare patches where weeds, without competition from surrounding turf grass, quickly become established.
Fertilize with a lawn fertilizer as often as recommended and at the application rate recommended on the fertilizer container label. Grass burr and goat head plants thrive in poor soil with little competition. A healthy strand of turf grass helps keep new seeds from sprouting by shading the soil.
Water the lawn deeply so water reaches 6 inches deep. Water as often as needed to keep lawn grasses from becoming stressed. Watering once every 10 to 14 days is enough to keep most lawns healthy during the dry season. Check for moisture depth by inserting a shovel or a screwdriver into the soil to see how far the moisture has soaked into the soil. Deep watering helps moisture get to the deep root zone of the lawn grass and away from the shallow-rooted grass burr and goat head plants.
For organic control, use corn-gluten meal at a rate of 20 lbs. per 1,000 square feet in the spring when the soil warms to 52 degrees Fahrenheit and again in late summer to prevent winter weed germination. Corn-gluten meal is not as effective as chemical control, however.
- Texas A & M University Agricultural Extension Service: Controlling Field Sandbur (Grassbur) in Turfgrass
- United States Department of Agriculture: Cooperative Extension System Offices
- New Mexico State University Agricultural Extension Office: Sand Burs and Goatheads in Lawns
- Alabama Cooperative Extension Service: Soil Temperature Conditions for Vegetable Seed Germination
- University of Minnesota Extension Service: Corn Gluten Meal: A Natural Pre-Emergence Herbicide