According to the calendar, spring is still several weeks away, but now is actually the perfect time to battle summer weeds. As you read this, thousands of tiny seeds are germinating under your beautiful lawn, preparing to sprout ugly weeds. Go on the offense with pre-emergent herbicides. If you act fast, you can stop the weeds before you ever see them.
Sure, you can wait and kill the weeds once they are visible, but weeds grow exponentially. After treatment, fewer weeds sprout, producing fewer seeds, and the cycle continues. With pre-emergents now and again in fall, you will make a significant dent your lawn’s weed population.
When to Apply Pre-Emergent Herbicide
Because these herbicides don’t work on dormant seeds or on plants that have already emerged, timing is important. Too early and the seeds won’t have germinated. Too late and the plants will already be up.
Warm Season Weeds
To eliminate 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 winter’s unseasonable weather affected blooming schedules this year.
To control winter weeds like annual bluegrass, henbit and common chickweed, you will need to reapply in the fall when the mercury slips between 65° and 70°F at night.
How to Apply Pre-Emergent Hebicide
Pre-emergents are available in both spreadable granules and sprayable options. Both need to be applied evenly across the lawn to work effectively. Most homeowners find the granules easiest to apply, but if you opt for the sprayable type, be sure to read the instructions carefully and mix accurately.
According to the UGA Extension Service, pre-emergents will not harm most established turf grasses, flowers, shrubs and trees.
WARNING: Pre-emergent herbicides can severely damage newly seeded lawns.
If you have a new or freshly over-seeded lawn, wait until the grass has been established for a full year before applying pre-emergents.
Unfortunately there is no magic bullet capable of eradicating the endless variety of insidious and persistent weeds. Although pre-emergents will not win every battle against every weed, they should be the mainstay of your arsenal. For the most common invasive weeds, applying pre-emergent herbicides twice a year will go a long way toward keeping your lawn beautiful year round.
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