Weeds and Your Lawn
Are Herbicides Really Necessary?
Before using herbicides consider the following:
- Are weeds at the right growth stage? Most herbicides are designed to work within a specific time frame. For example, pre-emergence products are effective only before germination. They are not effective on established weeds.
- Do you have the proper equipment? Is it calibrated to deliver the correct amount of product? Is the product appropriate for your weeds? Be sure to check the label.
- Are sensitive plant species nearby? Valuable plants can be harmed or killed if they come into contact with nonselective herbicides.
- What are the possibilities for off-site movement? Soil erosion, water, and wind can carry herbicides off-site, making them less effective and a source of pollution.
- Are weather conditions appropriate? Avoid applying herbicides during windy conditions or just before a heavy rain; drifting herbicides can cause injury to valuable plants or contamination.
- What will the cost be? How many applications will be necessary? Many persistent weed problems can be solved more efficiently by using different management strategies (e.g., choosing better-adapted grass varieties and planting ground covers that suppress weeds).
If you decide herbicides are necessary, reduce your risk of exposure by wearing protective equipment, as indicated on the label. Your local Cornell Cooperative Extension office can help you with information on particular products and how to sue them safely and effectively.
Smooth crabgrass-an annual warm-season weed found throughout the United States and Canada. Flowers resemble the digits on a hand. Germinates in several flushes throughout the late spring and summer.
White clover-a common perennial weed that reproduces by creeping stolons and seeds. Stems are prostrate, leaves are in threes, and flowers are pinkish white and fragrant.