Daniel Gill, Merrill, Thomas A. | 1/31/2006 2:19:48 AM
By Dan Gill
LSU AgCenter Horticulturist
Although our lawns are still dormant this month, you can begin to plan your strategy to have an attractive, healthy lawn this summer.
Since the grass is still dormant, most lawns look relatively bad now, so don’t judge yours too harshly at this point.
On the other hand, you can go ahead and identify areas where grass has died out completely and only bare soil remains. These areas will have to be repaired in April or May, and if you start planning for it now, you’ll know how much work you’ll need to do then. (Of course, you can simply wait until then to even consider the repairs if you’d like.)
There are several common causes of lawn thinning, including insect and disease problems, heavy traffic, poor soil fertility and too much shade. Poor maintenance, such as improper mowing and watering, also can be a factor. One or more of these problems may be affecting your lawn, and the situation may stretch back to last year or longer.
Mild winter temperatures and rainfall have created lush growth of winter weeds in lawns. Most cool-season weeds will not cause significant damage to a healthy lawn, so control generally is not critical. (Control is more important for cool-season perennial weeds, such as dollar weed and clover, however.). At any rate, I would recommend that you mow your lawn now and occasionally hereafter to keep the cool-season weeds that are growing in your lawn from flowering and setting seed. This will reduce weed problems next year.
You may apply a lawn weed killer now if you choose to. There are a number of commercial lawn weed killers available that control a wide variety of weeds.
If you decide to apply weed killer, make sure you choose one that is labeled as safe to use on the type of grass you have. You also should know what kind of weeds are growing in your lawn. If you don’t, you might take some to the nursery with you for help with identification. That way you can check the herbicide label to make sure the product you’re buying will control them. Follow label directions carefully to avoid damaging the turf or landscape plants.
Whatever weed killer you choose, do not use a weed and feed right now. It is too early to fertilize your lawn, and it will still be too early in March when lawns begin to green up. Research shows that turf grass does better if you wait until early to mid-April to make the first application of fertilizer to your lawn. If you have a weed problem that you need to deal with now, use a weed killer without fertilizer in it as recommended above.
One of the more common lawn diseases is brown patch – particularly with St. Augustine grass. This disease is caused by a fungus that thrives in cool, moist weather and causes areas of brown grass. Those areas can sometimes grow quite large, but most damage occurs in the fall, so there is no need to treat dormant grass now. This disease can kill the grass, but it is more common for it to weaken the turf. In turn, that causes the affected areas to green up poorly in the spring and makes the lawn more susceptible to weed encroachment. Should rainy weather this spring encourage new outbreaks (noticeable after the lawn greens up as new, rapidly expanding brown areas), active brown patch can be treated with a lawn fungicide such as Immunox and others.
Chinch bugs are not active now, but they also could have damaged your lawn last summer. These pests primarily are a problem from June through early October, and if areas of your lawn died during that time, the likely cause was chinch bugs. Unfortunately, these insects often kill the grass outright, and you will most likely need to replace the turf if it hasn’t greened up by May.
Lawn areas that have been damaged by wear and tear from dogs, children or foot traffic can be helped with extra care. In early April, use a garden fork to loosen the compacted soil in the bare areas, fertilize the damaged areas and all of your lawn and water the lawn regularly to encourage growth. Keep traffic to a minimum in the damaged areas until the turf has filled in. If a damaged area is large, you may want to loosen the soil and then lay new sod for faster coverage. Just keep in mind that if heavy traffic continues, the grass will be damaged again.
One of the leading causes of decline in turf quality is shade. As trees age, they grow larger and create more shade in the landscape. Areas where grass grew well before often become too shady for grass to thrive. Ultimately, landscaping the shady area with shade-loving shrubs, herbaceous perennials and ground covers will provide the best long-term solution.
Finally, this is not a good time to apply fill dirt over lawn areas, since the grass is not in active growth and will stay covered by the fill for many weeks. Wait to fill low spots or other lawn areas until May through September. Also remember that grass will only grow reliably through 1 inch to 2 inches of fill. If you need to fill something deeper, you may have to replace the turf in those areas. And don’t forget that trees can be injured or killed by excessive fill deeper than 2 inches that covers large areas of their root systems.
Get It Growing is a weekly feature on home lawn and garden topics prepared by experts in the LSU AgCenter. For more information on such topics, contact your parish LSU AgCenter Extension office or visit our Web site at www.lsuagcenter.com. A wide range of publications and a variety of other resources are available.