Most problems are easier to prevent than to cure. Weeds are like that, too.
By April, the weeds are several inches high and often have been growing for months. If we wait, the weeds are large, well-established and possibly have set seeds for the next generation. Control may be very difficult, if not impossible.
For our benefit, a quote from Ben Franklin is very applicable: “An ounce of prevention is worth a pound in cure.”
The weed flush from February through April is a result of seeds germinating from October through January. Prevent these weeds by spraying two applications of preventive herbicide.
Because weeds come up during a long period of time, two applications are needed. Spray a preventive (pre-emergence) herbicide about mid-October and then 45 days later around Dec. 1.
You also can prevent summer weeds with these chemicals. Summer weeds start germinating when temperatures get warm enough in the spring. Apply preventive herbicides in mid-February and again 45 days later in early April.
I prefer using Atrazine for weed control in the fall and winter. No herbicide prevents all weeds, but Atrazine controls more of the weeds we have in our area better than other herbicides.
Atrazine can be used on centipede, St. Augustine and Zoysia lawns. It cannot be used on green Bermuda grass, but you can use it on Bermuda lawns once they go dormant and are completely brown.
Atrazine controls many broadleaf weeds and a few grasses. The exception to this would be a lawn where crabgrass is the major problem. To prevent crabgrass, use Balan, Pendulum, Pre-M, Surflan or XL. Once again, you must put these out before weeds come up or they will not be effective.
For weed control in green Bermuda lawns, use Balan (benefin), Pendulum or Pre-M (pendamethalin) Surflan (oryzalin) or XL (benefin and oryzalin). Apply these at the same times mentioned earlier to prevent weeds.
It is critical to use these pre-emergence herbicides before weeds come up. Once weeds have germinated, these herbicides will not be effective.
Some herbicides can stress lawns. Be careful to use them according to the label directions. If the lawn was stressed from improper care the year before, consider not using a pre-emergence herbicide. Weakened lawns can be stressed or killed by herbicides.
Do not use a pre-emergence herbicide on lawns less than a year old. Let lawns get fully established before you begin using pre-emergence weed control.
Certain herbicides also will slow establishment of grasses. If you have bare spots in your turf, Balan, Pendulum, Pre-M, Surflan or XL can slow the growth of grasses into these areas. Avoid using these if you have bare spots you are trying to fill in.
There are a few other pre-emergence herbicides that may be available to homeowners — dithiopyr, Team, etc. See if the chemical controls your weed before you use it. Follow all label directions.
The primary weed control in lawns is not based on using chemicals. The best weed control program is a strong, healthy lawn.
Thick, healthy lawns shade and crowd out weeds. Keep your lawn healthy by proper watering, aerating compacted hard soils, proper mowing and sound fertilization programs.
A soil test is the only way to adequately determine what fertilizers are needed based on the soil nutritional levels. I will discuss that in my next column.
For more information, call me at 876-2133 or email robbell@uga.edu.