A healthy lawn may be the best defense homeowners have against invasive weeds, said Kansas State University horticulture expert Matt McKernan, adding that proper maintenance can prevent many common weed problems before they begin.
āWeeds invading a home lawn can feel like an ongoing battle,ā McKernan said. āInstead of constantly applying chemical treatments, homeowners should focus on growing strong, vigorous turfgrass that naturally crowds out weeds.ā
McKernan said healthy grass competes with weeds for sunlight, water and nutrients, making it harder for unwanted plants to take hold. He noted that many weed problems stem from common lawn care mistakes that weaken turfgrass and create opportunities for weeds to spread.
One of the most common problems is mowing grass too short. McKernan said scalping the lawn weakens turfgrass and allows more sunlight to reach weed seeds, encouraging germination. He recommends mowing at the proper height for the grass species, keeping mower blades sharp and avoiding mowing when grass is wet.
Watering practices also play a significant role in lawn health. Frequent, shallow watering encourages shallow root systems and can increase weed pressure, McKernan said.
Instead, homeowners should water deeply and less often to promote stronger roots and improve drought tolerance. During spring, irrigation should only occur when necessary.
Other factors that may lead to an unhealthy lawn include:
Ā· Improper fertilizing. Fertilizing too much or too little or at the wrong time may benefit weeds more than grass. Only fertilize during the recommended months, only apply what is needed, and conduct a soil test to better understand fertilizer needs.
Ā· Compacted soil. Soil compaction is a hidden stress on the turfgrass root system. The grass is unable to compete effectively with weeds. Core aerate lawns at least once per year to reduce compaction.
Ā· Excessive wear. Turf areas used for recreation, sports and pets are subject to wear and compaction. Core aerate to reduce compaction in these areas, and temporarily fence off areas when establishing new grass seed.
Ā· Wrong kind of grass. The wrong variety for the location will gradually decline and be invaded by weeds. Always check the grass seed label before purchasing to evaluate the types of grass seeds included in the bag. Purchase only recommended types of turf, avoiding cheap fillers.
Ā· Environmental stress. Weeds often take over a lawn after it has been weakened and thinned from weather-related stress. Water appropriately during times of drought and avoid overwatering in the spring and fall. Evaluate irrigation water quality and soil nutrient levels by testing.
Ā· Thatch. Excessive thatch causes shallow-rooted grass, limits water infiltration and contributes to insect and disease problems. Regularly monitor thatch accumulation and remove excessive thatch when necessary.McKernan said a proactive approach focused on lawn health is more effective and sustainable than relying solely on herbicides.
āA dense, healthy lawn is the first line of defense against weeds,ā he said.
Alicia Boor is an Agriculture and Natural Resources agent in the Cottonwood District (which includes Barton and Ellis counties) for K-State Research and Extension. You can contact her by e-mail at aboor@ksu.edu or calling 620-793-1910.
K-State Research and Extension is an equal opportunity employer and provider. Kansas State University, County Extension Councils, Extension Districts, and U.S. Department of Agriculture Cooperating.