Fall Lawn care

Lush green grass growing throughout the year is a challenge in the Piedmont.  Most gardeners select either cool-season or warm-season grasses for their lawns.  Charles Murphy brings us helpful tips for managing your turf and reasons for considering both types of grass.  Find out which one is right for you.

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MURPHY:  Hi, I’m Charles Murphy and I’m an NC State Extension Master Gardener Volunteer and I’m in Durham county.  Well, its lawn decision time again

This year I had one of the best lawns I’ve had in years, thanks to a combination of hard work, cooperative weather and some professional help for the big work. My tall fescue blend was a beautiful, lush deep green carpet, growing so exuberantly that it required two mowings a week for most of April and May. Now, however, it’s August, and my lawn has reverted to its customary midsummer brown color, splotched with even lighter patches of obviously dead grass. Without crabgrass I would have hardly anything green left. To be honest, this is largely the result of a decision to not water grass, saving watering for flower and vegetable beds. Having been down this road many times in the past, I could have written the script for late July, and onward, back in April. Prolonged high temperatures and our usual pattern of only scattered thunderstorms providing little in the way of useful rainfall took their all too predictable toll on my cool season lawn mix.

So now it’s decision time again. Do I choose the rehabilitate route, hoping for a better late fall lawn and early spring one, or do I make the move to a warm season grass, such as one of the hybrid Bermuda strains, or perhaps a Zoysia variety? Homeowners in our area face this decision practically every year, so let’s take a little time to explore the options and the upside and downside of each.

Lawn grasses are divided into two large classes: cool season grasses, which do best in moderate to cool temperatures with approximately one inch of rainfall/week; and warm season grasses, which are at their best in warm to hot weather, and which are usually more drought-tolerant than the cool season ones. Cool season grasses, mostly the fescue blends, stay green throughout the winter, but will go dormant, or even die, in our Piedmont summers unless heavily watered. Warm season grasses are brown in winter when they are dormant, but stay green throughout the hot summer months. Cool season grasses don’t spread, so they require periodic reseeding to fill in thin or bare areas; most of the warm season grasses spread by both above ground runners and underground roots, and will gradually fill in bare places in the turf on their own. With proper conditions and care, both types will make a thick, healthy turf that not only looks inviting, but discourages weed growth in the lawn.

In our decision-making, let’s take a few steps that would be common to either choice. First, take a soil sample for analysis if one hasn’t been done in the past two years. It takes about two weeks to get results back from the state lab, but since we can reseed a cool season lawn into early October in our area, it’s not too late. Second, assess your full-sun area. Both types of grasses require 6+ hours of direct sunlight/day for best results. (While there are some shade-tolerant varieties of fescues, “tolerance” doesn’t mean thriving.) Third, consider water requirements; we average 40-45 inches of rainfall/year in the Piedmont, but it’s not evenly distributed at ¾ inch/week, so extra water will be required at times.

If you plan to rehab/overseed, try to get rid of weeds in the lawn, either by hand-weeding or careful application of an herbicide. Consider adding a thin layer of topsoil and/or compost, (this is optional) plus fertilizer (1lb. nitrogen/ 1000 square feet), then core areate. Note: lime should not be added just because, “everyone else does it”, but should depend on results of the soil test analysis. A pH of 6.7 – 6.8 is OK for our usual lawn grasses. Lower than 6.5 would benefit from lime application, but remember that lime works into the soil slowly, and doesn’t assure immediate results. Areation helps to incorporate the additives into the top inches of the lawn, and allows air and moisture to penetrate into the root zone. Reseeding fescue can then be done according to product directions. Follow with regular watering to keep the seedbed moist; 2-3 times/day until germination, then twice/day for at least 7-10 days afterward. Further watering depends on rainfall, but should be at least once/day until seedlings are 3-4 inches tall. It’s important that new seed be in contact with soil in order to ensure germination and survival. Once new grass begins to grow vigorously, mow frequently enough to keep the overall depth of grass at 3 – 3.5 inches; mow regularly, and don’t cut the grass too close. After new grass is well-established, mow as needed to maintain uniform height. Fescue lawns should be fertilized in late summer, or at reseeding; in late fall (Thanksgiving); and late winter (late February). Fertilizing during summer months is unnecessary, and may lead to leaf growth at the expense of root development.

If the lawn is in such bad condition that just overseeding is not likely to produce good results, more drastic measures are in order. First, use an herbicide on the entire lawn area according to package directions. Wait 10 – 14 days (begin this in late August at the latest), then re-spray any weeds, or other green vegetation again. 8-10 days after the second spraying consider adding a thin layer of topsoil plus a layer of compost, fertilizer and core aerating. Then reseed over the entire lawn with a tall fescue blend according to package directions. Be careful to distribute the seed as evenly as possible, but keep in mind that extra heavy seeding isn’t necessary. Then, water regularly; three times/day for the first week, or until new grass begins to appear over the entire area, two times/day for at least one week, then once/day until new grass is obviously well-established. After that, water as necessary to as average 1”/week. When new grass is 3-4”tall, mow to a height of 3-3.5 “. Remember, fescue grasses do best when cut tall. Too close cutting forces the new grass to put more energy into growing new leaves than into growing new roots. Frequent mowing may be necessary, but better to cut tall twice/week than short once/week.

If a switch to warm-season grass is planned, treat the lawn as for cool-season grass, but seed with annual rye grass instead of a fescue blend . This will maintain a green lawn through winter, but won’t interfere with establishment of new grass later. In mid to late May, prepare the seedbed by adding a layer of topsoil, then seeding (if possible) or laying sod. Laying sod is the most reliable and quickest way to establish a warn-season grass, but is labor intensive and expensive. As with any new lawn, water frequently, and deeply, until new grass is established. Warm-season grasses should usually be fertilized at seeding, then in late May or early June, and again in July. Later fertilizing will result in new growth that may result in frost damage in mid-autumn. These grasses will go dormant and turn brown naturally in winter; they will green up again in April-May. They should be mowed closer than fescue lawns – no more than 1.5 inches tall, this encourages spreading- and watered as necessary to maintain a green appearance.

In the mid-south piedmont we live in a transition zone where growing a lush, green lawn is always a process that requires constant attention and, often, lots of labor and water. If we continue to experience hot, dry summers, then warm-season grasses are probably the best choice in the long run. If the climate changes to give us cooler and wetter summers, then cool season grasses will be the default choice for most home gardeners. Which path you choose depends on individual preferences as much as any other factor. But, the question always remains: how much lawn do I need, and is it worth the cost? There are alternatives that are well worth exploring, for example switching to a different season grass, expanding flower beds to reduce grass area, and/or introducing ground covers that require little maintenance once established, don’t neglect them.

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