As many turfgrass professionals know, the best defense against common weeds is a good offense. Unfortunately, home and business owners often wait for warm weather to think about lawncare—long after many summer weeds have already sprouted. Whether you provide maintenance or not, educating your clients about pre-emergent herbicides could win you customer service points while keeping their lawns looking great through summer.
What is pre-emergent herbicide?
Each spring, thousands of seeds germinate under the soil line, preparing to sprout into common weeds, spoiling the uniform look of well tended turfgrass. As the name suggests, pre-emergent herbicides kill weeds before they emerge or sprout above the soil line.
These effective treatments are formulated to prevent germinated seeds from maturing, stopping weeds before they are visible. After treatment, fewer weeds sprout, producing fewer seeds, and the cycle continues. With regular pre-emergent applications, property owners or their lawn maintenance service can make a significant dent in a lawn’s weed population.
Always encourage clients to read product instructions and warnings carefully, but pre-emergent herbicides are generally safe for most grass varieties, including Bermuda, zoysia, centipede and tall fescue.
When to apply pre-emergent
Because these herbicides don’t work on dormant seeds or on plants that have already emerged, timing is important. Many property owners wait too long when the plants are already visible and difficult to kill selectively.
To prevent warm season weeds like crabgrass and goosegrass, apply pre-emergents in late February or early March before soil temperatures reach 55°F. Usually the blooming forsythia marks the perfect time to apply, but unseasonable winter weather may affect blooming schedules.
Additional applications of pre-emergent herbicide in early and mid-summer will help ensure effectiveness, and repeated heavy rains may call for reapplication. To control winter weeds like annual bluegrass, henbit and common chickweed, apply in the fall when the mercury slips between 65° and 70°F at night.
How to apply pre-emergent
Pre-emergents are available in both spreadable granules and sprayable options. Both need to be applied evenly across the lawn to work effectively, and both should be watered-in either with light irrigation or just before a rain. Homeowners may find the granules easiest to apply, but many pros have access to equipment that makes the liquid type preferrable.
According to the University of Georgia (UGA) Extension Service, pre-emergents are safe for most established turf grasses, flowers, shrubs and trees, however these herbicides may cause severe harm to newly seeded lawns. If you are treating a new or freshly over-seeded lawn, UGA recommends waiting until the grass has been established for a full year before applying pre-emergent.
Barricade, or the generic Prodiamine, is a good product to recommend to clients who maintain their own lawns, since it is readily available through Amazon and offers significant weed prevention with only two applications per year.
Although pre-emergents will not win every battle against every weed, they should be the mainstay of any lawn maintenance arsenal. For the most common invasive weeds, applying pre-emergent herbicides at least twice a year will go a long way toward keeping your clients’ lawns beautiful year round.
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