Lawn Weed Control

Weeds

A weed is simply a plant that is growing in the wrong place. These misplaced plants in our lawns not only compete with the desirable grasses for nutrients and water, but also take away from that "picture perfect look". Where do they come from? Animals, water and wind carry weed seeds from place to place. Even more are released when weed plants are allowed to go to seed; some plants produce over 100,000 seeds in a single season! Other weeds spread by means of underground stems. Fortunately, there are several effective methods of control from which to choose.

Weed Prevention

A vigorously growing lawn is the best insurance against weed problems. Improper care, such as over or under watering, mowing the lawn too short, low fertility, excessive wear, insects, and diseases may cause lawns to thin, opening up spaces for weed invasion.

When establishing a new lawn, reduce weed invasion by following proper cultural procedures and purchasing quality materials. The ideal time to start a lawn is in the fall when the temperature is optimal for root growth, and there is usually ample moisture and less competion from weeds. Purchasing quality grass seed suited to your lawn's site and usage will help prevent weed seeds from either being introduced or gaining a foothold.

Weed Control

Even when the correct practices are followed, weeds can still become a problem. Identifying the weed is essential so that the proper management method can be selected. Preemergent Control is used most often for annual grasses such as crabgrass. This type of weed killer is applied before the seeds germinate. The best time to apply crabgrass control in our area is from the middle to end of March. Unfortunately many of the chemicals used to prevent the germination of crabgrass can also be harmful to desirable grass seeds.

If the seeding of a new lawn is planned for the spring be sure to select an herbicide which contains chemicals like tupersan that will permit reseeding immediately. Postemergent Controls are applied to weeds that are actively growing. These chemicals are absorbed through the leaves and translocated to the roots, killing the entire plant. There are two types of postemergent weed control; selective and nonselective. Selective weed killers are effective against specific weeds but don't harm desirable lawn grasses.

Elimanating weeds such as dandelion or clover from an established lawn requires selective postemergent weed control. Non-selective controls kill all contacted vegetation and are useful for lawn renovation and spot-treatment of difficult to control weeds. Be careful not to get these non-selective herbicides on or into the root zone of desirable plants.

Liquid vs. Granular

Herbicides are available in both liquid and granular formulations. Pre-mixed liquids in ready to use containers are handy for spot treating a few weeds. Concentrated liquids applied with a hose end sprayer work well on large areas. Large areas may also be treated with granular herbicides applied by means of a lawn spreader. Many lawn fertilizers also contain herbicides and are referred to as "weed and feeds". Granular forms are availabe in sizes to cover from 5,000 to 10,000 sq. ft. Follow label instructons when applying any herbicide.

Wet or Dry Lawn?

This decision depends on the way the chemical works. The objective of a weed preventer is to form a chemical barrier at the soil line to inhibit seed germination. These chemicals should be applied to a dry lawn and then watered into the soil. Granular broad leaf weed killers require maximum foliage contact and therefore must be applied to a wet lawn so they will stick to the foliage. Never use sprays on windy days to minimize drift.