This article was in the Dallas Morning News yesterday. Very interesting information about why SA is having trouble this year.
Flower Mound, TX
St. Augustine lawns suffered from this year's extreme weather
04:03 PM CDT on Wednesday, October 13, 2010
By KARA KUNKEL / Special Contributor to The Dallas Morning News
If you have a St. Augustine lawn, did it look pathetic this year? Many did. Lawns in North Central Texas suffered more than usual, primarily because of extreme weather.
RON HEFLIN/Special Contributor
A combination of deep freezes, record snowfall, heavy rains and prolonged 100-degree days dealt a mortal blow to a good-size patch of lawn at an Old East Dallas address. "This was probably one of the hardest years on St. Augustine grass lawns that I have seen in a long time," says Dr. James McAfee, the turf grass specialist for Texas AgriLife Extension Service in Dallas. He compares the damage to what occurred in 1988-89, when "a hard winter froze lawns worse than this year."
McAfee cites three major problems that have distressed St. Augustine lawns and their owners this year:
â€¢Deep freezes and record snowfall during late winter contributed to a condition called winterkill, which became evident when lawns failed to revive after spring weather warmed the soil.
â€¢Lack of water, insect damage and diseases from the previous fall also weakened grass and made it susceptible to winterkill.
â€¢Unusually heavy midsummer rains increased humidity and created ideal conditions for rampant growth of a fungal disease called gray leaf spot, which damaged many St. Augustine lawns that survived winter freezes.
Gray leaf spot causes lesions on grass blades, which gradually turn brown and die. Heavily afflicted lawns are weak and may look thin and brown.
Extremely hot and dry August weather put additional stress on St. Augustine lawns. If irrigation was not increased to compensate for the weather, drought further weakened turf and made it susceptible to diseases and insects. Some lawns that started the year weakened by freezes lacked the strength to survive 105-degree temperatures combined with drought, McAfee says.
Saying that many lawns experienced similar problems isn't the same as saying that owners are guiltless. McAfee says gardeners can do a better job of preparing lawns to cope with severe weather. Even when a lawn is so badly damaged that resodding is the best solution, an involved and observant owner often can prevent future catastrophic turf loss by following good maintenance practices.
"The average gardener does not pay attention to the lawn, and you need to be observant," McAfee says.
To raise a healthy, vigorous lawn, North Texas gardeners should constantly monitor temperature, rainfall and irrigation data and adjust irrigation and mowing as needed, he says.
With relatively mild fall weather on the horizon, this is a good time to improve lawn care habits. Mowing, irrigation and fertilization are good places to start, McAfee says.
Mow St. Augustine lawns at least once a week this fall and more often if possible. McAfee says he has created a lush lawn by mowing twice a week during the growing season to prevent dramatic changes in the length of grass blades and to encourage thick growth. The grass also produces more roots, he says, which improves the absorption of water and nourishment.
Water is important year-round. During the growing season, a St. Augustine lawn needs about an inch a week from rain and irrigation. Once the lawn is dormant, set a goal of 1 inch every four or five weeks, McAfee says. Automatic sprinkler systems can be turned off during winter, but gardeners should continue to monitor rainfall and supplement it as needed.
During fall, use a fertilizer with a 3-1-2 ratio (the ratio of nitrogen, phosphorus and potassium in the fertilizer), unless the results of a soil test indicate that more phosphorus or potassium is needed, McAfee says.
Watch for fall diseases such as brown patch, a fungus that forms circular brown patches in the lawn. Consider using a fungicide to treat severe cases, he says.
Howard Garrett, who writes an organic gardening column for The Dallas Morning News, agrees with much of what McAfee recommends, but he believes that chemical fertilizers, fungicides and insecticides do more harm than good.
Garrett says his observations indicate that organically maintained St. Augustine lawns survived last winter's freezes better than those where chemical fertilizers were used.
"More trace minerals in the plants means ... more stress tolerance," Garrett says. "We have seen this on organic projects for years."
He also believes that using high-nitrogen fertilizers makes a lawn vulnerable to fungal diseases. When a St. Augustine lawn is attacked by a fungus such as brown patch or gray leaf spot, Garrett says, gardeners should avoid chemical fungicides and use organic remedies such as cornmeal, cornmeal juice, mild horticultural soaps, garlic and compost, which he recommends on his website (www.dirtdoctor.com
Rather than using a synthetic fertilizer this fall, Garrett recommends that gardeners spread compost, an organic fertilizer and dry molasses over the lawn.
If part or all of a St. Augustine lawn has died, you can safely replace the damaged sod through late October, depending on the weather, McAfee says. Plant sooner rather than later to reduce the risk of freeze damage. Raleigh and DelMar are the best St. Augustine varieties for North Texas because they tolerate freezing weather better than other varieties and are resistant to a deadly viral disease called St. Augustine decline, he says. There is no cure for St. Augustine decline, which is spread from one lawn to another by mowing equipment.
Kara Kunkel is a Dallas freelance writer.
Lawn trivia worth knowing
Nuggets of wisdom that Dr. James McAfee of Texas AgriLife Extension Service has acquired during more than 30 years as a turfgrass expert:
"The worst thing you can do for gray leaf spot or brown patch is to put out fertilizer because nitrogen makes the problem worse" by causing grass blades to grow and feed the disease.
"We lose more grass to desiccation in the South during winter than to anything else" because gardeners turn off automatic sprinkler systems and stop paying attention to their lawns.
A few grub worms (the soil-dwelling larvae of June beetles) are not a cause for drenching the lawn with insecticide. Finding more than four or five grubs per square foot is the threshold for treatment.
Grass doesn't grow well in compacted soil. Aerate the soil to loosen it, which brings more oxygen to the root system and allows water to penetrate the surface more easily. Aeration is a mechanical process that removes plugs of soil at predetermined intervals.
Don't overseed a St. Augustine lawn with ryegrass for winter if you want a thick, lush lawn in summer. "I strongly advise against overseeding with rye because it puts stress on the lawn," McAfee says. In addition to disrupting St. Augustine's season of rest, planting ryegrass requires gardeners to cut a lawn short during the time it should be using grass blades to store nourishment for winter and spring.
Dead grass turns gray. Dormant grass is light tan. The first is cause for concern, but there's little to worry about on the second.