The grass is always greener when somebody else is doing the work. Perfect abdominals and perfect lawns are the stuff of infomercials and obsessed individuals.
Once the lawn starts to grow it seems as though it constantly requires mowing, edging, fertilizing, weeding, watering and fretting, says Jerry Goodspeed, Utah State University Extension horticulturist.
"Unlike many showcase yards, my lawn is simply a place for the children to play, a soft bed for book reading on a warm evening or a place for the family to gather for a picnic or soccer game. A few weeds usually don't cause me too much heartache. When the weeds start dominating the grass, I figure it's time to take action."
The most important weed control method for the lawn is keeping it healthy, Goodspeed says. Creating a perfect environment for the grass creates a less favorable environment for most weeds. Unfortunately, most people often over-water and mow too short, which creates an ideal environment for weeds.
He suggests mowing the lawn no shorter than 2 « to 3 inches high. This gives it an advantage over low-growing weeds. Water 1 to 2 inches a week as infrequently and deeply as possible. Every 5 days or so, during hot summer weather, and less often during the cooler months is sufficient.
"Other than dandelions, the two most troublesome weeds in many lawns are crabgrass and spurge," Goodspeed says. "Over-watering encourages crabgrass, and creates a favorable environment for its growth. Spurge loves a thinning lawn that is mowed too short. These two pests are annuals, meaning they start from seed every spring or early summer, and die out each winter with the first freeze. They are most troublesome in the middle of the summer, but germinate and start growing in the spring."
Goodspeed says a pre-emergent herbicide helps reduce these two most common weeds. These selective herbicides are applied to the ground before the weeds emerge only killing newly germinating weeds and allowing most established plants to continue growing.
"Pre-emergent herbicides do not stop seeds from germinating, nor do they prevent most perennial weeds from emerging from their established root systems and rhizomes," he explains. "Rhizomes have enough energy to push through the pre-emergent. Established weeds such as dandelions, clover, and perennial grasses, are unaffected."
Most pre-emergents need to be applied in April, and then again the first of June, Goodspeed says. Weeds germinate once the soil and weather reaches a certain temperature, so an exact date each year is hard to pinpoint.
"Driveways, sidewalks, and other man-made structures and surfaces tend to warm the surrounding soil quicker than other areas of the lawn. These may become weed problem areas," he says. "I have seen extreme problems in some lawns where the weeds congregate around these areas. A pre-emergent may need to be applied sooner to these areas prone to early warming. This will prevent those nasty annual weeds that hang out by the driveway."
For more information, contact your local USU County Extension office.
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Issued in furtherance of Cooperative Extension work, Acts of May 9 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Robert L. Gilliland, Vice-President and Director, Cooperative Extension Service, Utah State University, Logan, Utah. (EP/09-98/DF)