Although our lawns are still dormant this month, you can begin to plan your strategy to have an attractive, healthy lawn this summer. Because the grass is still dormant, most lawns look relatively bad now, so don’t judge yours too harshly at this point.
You should 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. Otherwise, wait until late April or May to evaluate your lawn and make final decisions on any repair work that may be needed.
Lawn thinning can be caused by several common problems, including insects and diseases, 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 cause may stretch back well into the past.
Winter weather does not stop the lush growth of winter weeds in lawns. Most annual cool-season weeds will not cause significant damage to a healthy lawn, so control is generally not critical.
I would, however, recommend that you mow your lawn now and occasionally hereafter to keep any cool-season weeds from flowering and setting seed. This will reduce annual cool-season weed problems next year.
You may apply a lawn weed killer now if you choose to. Control with herbicides is more important for cool-season perennial weeds, such as dollarweed and clover.
A number of commercial lawn weed killers are available to control a wide variety of weeds. Make sure you choose one that is labeled safe to use on the type of grass you have.
You should know what kind of weeds are growing in your lawn – you might take some to the nursery for identification – so you can check the herbicide label to make sure the product will control them. Follow label directions carefully to avoid damaging the turf or landscape plants. Two applications generally provide the best control.
Whatever weed killer you choose, do not use a weed and feed. It is too early now to fertilize your lawn, and it will still be too early in March when lawns begin to green up. Research shows that turfgrass does better if you wait until early to mid-April to make the first application of fertilizer. If you have a weed problem that you need to deal with now, use a weed killer without fertilizer in it.
One of the more common lawn diseases is brown patch, particularly for St. Augustine grass. This disease is caused by a fungus that thrives in cool, moist weather and causes areas of brown grass that can grow quite large. Most damage occurs in fall, and 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, causing the affected areas to green up poorly in the spring and make 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.
Chinch bugs are not active now but could have damaged your lawn last summer. They are primarily a problem from June through early October. 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 any bare areas, fertilize the lawn – including the damaged areas – and water the lawn regularly to encourage growth.
Keep traffic to a minimum in the area until the turf has filled in. If the area is large, you may want to lay new sod for faster coverage after loosening the soil. 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. Often, areas where grass grew well before 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 add any fill over lawn areas because the grass is not actively growing and will stay covered by the fill for many weeks. Wait to fill lawn areas until May through September. Grass will only reliably grow through 1 to 2 inches of fill. If you need to fill deeper, you may have to replace the turf in those areas.
Don’t forget that trees can also be injured or killed by excessive fill covering large areas of their root systems deeper than 2 inches.
Dan Gill is a horticulturist with the LSU AgCenter. He can be reached at DGill@agcenter.lsu.edu