Effective and Safe Herbicide Applications

Ensure lawn herbicide applications are safe and effective by following the tips below.

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  A wicking applicator used to apply herbicides directly to weeds.
  Photo by Steve Manning, Invasive Plant Control, Bugwood.org

  Correctly identify the weeds. Herbicides vary in their control of different weed species. Preemergent herbicides are effective at controlling certain weeds, while regular mowing may efficiently manage other weeds. Choose the most effective control method after correctly identifying the weed.

• Read the entire herbicide label. The label contains all the information needed to apply the chemical safely, including mixing and application instructions and timing.
• Treat weeds when young and small. Most herbicides are less effective once weeds are mature and begin to produce flowers and seeds.
• Do not mow turfgrass three to four days before and two to three days after herbicide applications to avoid lawn damage and ensure adequate chemical absorption. Some herbicide labels require no mowing seven days before and seven days after an application. Read the label.
• Mind spray droplet size. Adjust spray droplet size to produce droplets that coat the leaf surface adequately without causing excessive runoff or allowing the pesticide to drift off-site.
• Do not apply herbicides to warm-season turfgrasses during spring transition due to the potential for lawn damage. Mow newly-sodded and seeded lawns three times before applying herbicides.
• Do not apply herbicides when air temperature exceeds 90 ºF. Many herbicides have temperature restrictions due to surfactants in the mixture that can damage the grass.
• Irrigate or wait for the rain to fall a day or two before herbicide applications to limit possible injury and enhance herbicide uptake and control. Drought-stressed weeds take up chemical sprays less effectively.
• Do not apply herbicides when wind speeds are over five mph to avoid drift onto desirable plants. Use sponge applicators to apply herbicides to weeds in landscape beds directly.

For more information on lawn weed control, please see HGIC 2310, Managing Weeds in Warm Season Lawns and HGIC 2309, Managing Weeds in Fescue Lawns.