Iwrite about weed control in lawns a lot in my columns because that is one thing people ask me so much about.
Most of the time people ask what they can put out or spray to kill them. Using herbicides whether pre- or post-emergence is all fine and good, but you must look beyond herbicides for weed control. Herbicides should only be the last line of defense.
You have to take a look at the total management of a lawn.
If your grass is not doing well, that is your first problem. Weeds don’t overtake a thick, healthy lawn.
Weeds detract from the natural beauty of a desirable turf grass and compete for sunlight, soil moisture and plant nutrients. Certain weed species, such as crab grass, can become the dominant species in a lawn without proper control practices.
Weeds don’t easily invade turf grasses that are properly fertilized, watered and mowed at the correct height and frequency. Weeds appear primarily in lawns with bare or thin areas of turf.
The following practices will help to prevent weed infestations in home lawns:
Select and establish a turf grass adapted to the site or area. For example, tall fescue is an excellent permanent turf grass in north Georgia, but a poor choice for the Augusta area because of its inability to survive the hot summer. Bermuda makes a fine lawn, but it needs lots of sun (exceptions are Celebration and TifGrand). If your yard is shady, it will not grow well.
Apply the proper amount of fertilizer and lime at the correct times of the year. Centipede requires only 1 pound of nitrogen per
1,000 square feet per year. Hybrid Bermuda requires
4 to 6 pounds of nitrogen per 1,000 square feet per year. Overfertilizing centipede will promote decline and lead to increased problems with weeds.
The different turf grasses vary dramatically in their fertility needs. Soil testing through a county extension office is the best way to determine the exact amounts of fertilizer and lime that
When the results come back, pay special
attention to the pH and potassium levels in the soil. Both are extremely important in growing a quality lawn.
Water properly and only when needed. Frequent, shallow watering will help weed seeds germinate and grow. This continues to be one of the biggest mistakes I see in home landscapes.
Most turf grasses in Augusta need 1 inch of rainfall or irrigation every five to seven days during the growing season. This is the amount you start with. Vary your watering based on the soil type and species of grass that you have. Irrigate only when you don’t get
that much rain. Don’t set your irrigation system and forget it.
Infrequent irrigation that wets the soil from 6 to 8 inches deep will promote turf grasses to grow deep roots and compete well with weeds.
Mow turf grass at the correct mowing height and frequency. Because they need to be fertilized differently, the various turf grasses need to be mowed at different heights, too.
mowing height for St. Augustine is 2 to 3 inches, while hybrid Bermuda is 0.5 to 1.5 inches.
Generally, mow any turf grass often enough so that only one-third of the leaf area is removed at any one time. Removing too much leaf or mowing below the recommended mowing height will stress the turf grass and make it less able to compete with weeds.
Remedial actions might be necessary to control diseases or insects, which can decrease the stand of the turf grass. Fortunately, the practices that limit weed encroachment will also limit disease and insect problems.
Use herbicides to control weeds only after following proper turf grass management practices. If your grass is stressed and not healthy from something I have mentioned previously, herbicide labels will instruct you not to use them.
Herbicides should only be used to supplement weed control you achieve through proper turf grass management.
A variety of weeds can be a problem in home lawns. However, proper turf grass management, the first line of defense against weeds, can control many of these to an acceptable level.
REACH SID MULLIS, THE DIRECTOR OF THE UNIVERSITY OF GEORGIA EXTENSION SERVICE OFFICE FOR RICHMOND COUNTY, AT (706) 821-2349 OR SMULLIS@UGA.EDU.