Bob Westerfield is the extension consumer horticulturist for the University of Georgia. Adrianne Todd is Bob’s technical assistant at the University of Georgia Griffin Campus.

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Turf Rescue 911
by Bob Westerfield       #Turf Grass

When it comes to the months of the year, I have to admit that August is not among my favorites. While I am very much an outdoor person and enjoy working in my garden and managing my small farm, I do not enjoy the blistering heat and humidity that August almost always provides. Many years ago, my father was transferred to the South, and I have somehow endured the summer heat of August ever since. Thank goodness for air-conditioning! While I can step inside to cool off and enjoy the benefits of my A/C unit, my turf grass has no choice but to endure every heat wave that Mother Nature throws at it. While most turf grasses handle the summer heat better than we gardeners can, August will still take its toll on the health and survival of your lawn. By following a few rescue procedures, you can bring your lawn back from heat exhaustion and help it look better during this most infernal month.

Core aeration is a key component to late-season turf survival. Aeration breaks up soil compaction and allows for more efficient penetration of water, nutrients and oxygen.

During times of stress or drought, raise the mower deck up one or two notches to allow more leaf blade to remain. 

Hot temperatures and high humidity can cause rampant diseases during the late summer months. 

One of the first priorities for any turf grass during the hot summer months (August, in particular) is soil moisture. Although August provides some areas of the South with frequent pop-up thunderstorms, they often provide very little moisture that actually makes it into the soil. Rainfall from heavy thunderstorms frequently runs off the surface of our compacted soils and never actually penetrates into the soil. If it was possible to order rain, our preference should be a sustained, light drizzle that slowly penetrates the soil surface. Unfortunately, we are unable to control our weather, so we have to take other actions instead. Whenever possible, irrigate your lawn at the first signs of stress in the leaf blades. Stressed leaf blades typically turn a light bluish color and begin cupping or closing as they become drought stressed. This is the ideal time to water the lawn. During hot and dry periods, it is far better to water the lawn slowly and thoroughly than frequently and lightly. Light, shallow waterings will only tease the lawn and encourage shallow roots. Furthermore, most applied moisture evaporates quickly into the atmosphere. Not everyone has an automated irrigation system; I don’t have one at my house, either. But I do find it fairly effective to irrigate with a slow-moving sprinkler tractor that glides along the hose as it waters. Not only are they effective at irrigating large areas thoroughly, they are also fun to watch. You can also use single or multiple portable sprinklers as an option if you have nothing else. It may take several hours of irrigation to penetrate to a depth of 4 to 5 inches, but this is what you need to do.

In addition to irrigating, I like to assist my lawn by aerating it in August. After months of blazing summer sun and compaction caused by the weight of the lawn tractor and foot traffic, aeration will bring much-needed relief to your soil and turf. Core aeration is the preferred method and will pull up small plugs of soil and turf as you work the area. While this causes minor injury to the turf, its benefits far outweigh the disruption it causes. The holes created by aeration will allow a much more efficient exchange of moisture and oxygen. I have been amazed by how quickly my turf recovers and responds to thorough core aeration. Warm-season grasses should be aerated in August. Cool-season grasses, such as fescue, should be aerated in the fall during their normal peak period.

When rescuing turf during the hot summer months, you must pay particular attention to the height of your grass. Usually, the rule of thumb (regardless of the turf grass type) is to remove no more than one-third of the grass blade per mowing. During periods of high heat and drought when supplemental irrigation is unavailable, raise the height of your mowing deck one or two notches to maintain the grass at a slightly higher level. Be sure to keep your mower blades as sharp as possible, which may require removal and maintenance. By August, mower blades are often dull, and we rarely stop to check and maintain them. Sharp blades make for a more attractive and healthier cut on our turf grass.

Nutrition also plays a large role in how healthy our turf appears during the late summer months. Because most of the initial fertility we applied in the spring has now been used, it may be necessary to give our lawn another feeding. If you have not already done so, send a soil sample to your local county extension office to determine the fertility needs of your turf areas. Often after the initial fertilization in the spring, the only addition necessary in late summer is a light dose of nitrogen. Do not, however, fertilize your lawn if it’s under severe drought stress. The extra salt found in the base of the fertilizer may damage the turf, rather than benefit it. If you do fertilize, try to apply it just prior to a rainstorm or irrigate immediately after application.

By late summer, many of the insect and disease problems that may occur in your lawn will begin to manifest themselves. High humidity and rain may actually induce the diseases that occur in your turf. When checking your landscape for disease, look for discolored or brown areas of turf that gradually increase in size. Check for disease early in the morning while grass is still wet — you can often see the reproductive spores of the disease at the edges of brown patches. If you suspect a disease problem, it’s best to consult with your county agent or bring a sample of the infected material to their office. Different diseases require different solutions, including the application of fungicides or the modification of management practices. Insects may also take their toll on turf grass during the hot summer months. From white grubs to spittlebugs, these lawn pests will chew and suck the life out of our turf grasses. Those with St. Augustine turf may experience a nasty little insect called the chinch bug. This pest is often difficult to spot before it causes large areas of St. Augustinegrass to discolor and eventually die.

When determining a treatment method for diseases or insects, it is imperative to make a proper identification in order to arrive at the correct solution. Not all insects are bad, and not every turf disease will affect our lawn. Often by simply increasing the health of our turf through proper fertility, irrigation and sound mowing practices, we can prevent or eliminate disease and insect problems. When a problem does become serious, it’s crucial to attack it with the proper insecticide or fungicide for that specific problem.

Help your lawn survive the severe heat of August by keeping a closer watch on it than you did during milder months. Just as you and I feel uncomfortable in the extreme heat, these conditions may also cause adverse effects in your turf. Through proper management — including nutrition, irrigation and other practices — you can help your lawn get through this difficult month and prepare it for the cooler temperatures to come.


Photos courtesy of Bob Westerfield.


Posted: 07/30/12   RSS | Print


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