Going for the green: how to prepare your turf before the drought season.

The mild, drizzly summer that encompassed much of the country in 2004 made it easy to forget about the scorchers of the past, when watering bans and parchment-colored lawns were commonplace. Looking forward to summer 2005, no one knows what the weather will bring in terms of precipitation and heat. But if that old saying is true that says, "The weather is never the same two years in a row," we may be in for a real doozy.

There's not much anyone can do to control the weather. But there are some valuable maintenance practices to help prepare turf to tolerate a drought; both before drought hits, and afterward as a means of repair. These tips are useful whether or not you have irrigation available at your park facility. There have been some breakthroughs in understanding drought, and how these practices can be employed in practical terms to help your lawn sail through a troublesome summer. Even with preparedness, there are many misconceptions in the landscape industry about drought. For example, you may have seen extensive bulletins or conservation Web sites promoting, "Mow high and mow often for water conservation." Research has shown that this advice is entirely false.

Resisting Drought

With the increasing environmental awareness in recent years, turfgrass researchers have undertaken hundreds of research studies on lawn water use. Today we know much more about water than we did just a generation ago. Early studies on turfgrass water were brief and simple--perhaps a bit too simple. In one study, researchers grew grasses in flower pots in a greenhouse. After the grasses were well established, the researchers withheld water until the first ones died. They concluded that these grasses were not drought-hardy.

While studies like this can give an interesting glimpse into water use, they obviously don't answer all the questions. Deep-rooted grass in such a trial would show no advantage--the root system was only as deep as the cup. Thus, many early trials related poorly to real-world conditions.

The drought endurance trial later moved from the greenhouse to the field, making use of natural growing conditions. An early field study at Texas A&M University tested a series of grasses during a freakish 158-day summer drought. Adding to the severity, researchers grew the grasses on sand (which retains very little moisture) and with no irrigation. The researchers found that a number of grasses survived the torturous drought. Bermuda grass faired virtually unscathed, followed by zoysia grass and Kentucky bluegrass. (Yes, Kentucky bluegrass! Environmentalists have always painted bluegrass as a villainous water guzzler. But according to the Texas study, it proved to be a survivor.) Centipedegrass and St. Augustine grass were intermediate in drought resistance.

Even more striking were the drought differences among grass varieties. Two varieties of the same species behaved radically different. Author of the study James Beard says, "This data emphasizes that when selecting water-conserving turfgrasses, it is important to specify the cultivar [variety] as well as the species."

Each year the National Turfgrass Evaluation Program (NTEP) examines drought and other turf attributes in a series of university test trials across North America. These trials are similar to the familiar All-American Flower trials, except emphasis is placed on endurance as well as beauty. In recent trials (available online at www.ntep.org), drought-hardy Kentucky bluegrass varieties included Award, NuGlade, Odyssey, Rugby II, Total Eclipse and Unique. Admire, Affinity, Applaud and Passport scored well in drought among perennial ryegrasses. Arid, Brandy, Lion, Pixie and Rembrandt were drought-tolerant tall rescues, as were Ambassador, Ambrose, Brittany and Jamestown II fine rescues. Among the warm-season grasses, Riviera and Shanghai-seeded bermudagrass resisted drought, as did El Toro, Emerald, J-37 and Meyer zoysia.

Another key element in drought preparedness is matching the right grass to the right landscape situation. A grass is water-efficient only when it is well-suited to its climatic zone and location in the landscape. Bermudagrass and zoysiagrass are two of the most water-thrifty grasses. They have deep roots, an efficient physiology, and a biological mechanism for shielding their regenerative buds from permanent dehydration. As a result, they can return from prolonged droughts that would wipe out other species. Bermudagrass and zoysiagrass are best suited to landscapes from Virginia to Georgia and from Southern Kansas to Northern Texas.

Placed in the wrong location, however, a desirable grass quickly loses its advantage. Bermudagrass is valuable only in full-sun areas, because it doesn't persist in shade. Zoysiagrass is slightly more shade-tolerant than bermudagrass, and can persist up to a tree trunk with judicious pruning. If used beyond their adaptation belt, both grasses become thin and give way to weeds and other grasses. Bermudagrass conforms to virtually any turf application from golf courses to road sides. Zoysia is more restricted: You seldom see zoysia grown on sports fields and playgrounds due to its miserably slow recovery from wear.

Centipedegrass and St. Augustine grass are the classic broad-bladed lawngrasses of the deep South. Centipedegrass thrives in a belt from Georgia to Oklahoma; St. Augustine grass is adapted to the south of there. Both species have better shade tolerance than bermudagrass, but consume more water.

In the North, Kentucky bluegrass is the primary grass for golf course fairways, sports fields, parks and play areas--in speckled shade or full sun. Tall rescue is a coarse-bladed, wear-tolerant grass well-suited to athletic turf. It is seldom used on fine turf due to its rough appearance. Perennial ryegrass has many of the same uses as Kentucky bluegrass, but with an adaptation range similar to tall fescue. Adaptation of tall fescue and perennial ryegrass straddles the Mason-Dixon line. When used too far north (Minnesota, Wisconsin and New England), tall fescue and perennial ryegrass periodically winterkill. Likewise, if pushed south of the Carolinas, summer diseases take their toll. Kentucky bluegrass is winter-hardy and can be grown north into Canada.

Myths and Misconceptions

The turfgrass research performed throughout the last two decades has rewritten the textbooks on how to handle drought. Many of our past beliefs have proven to be dead wrong.

Tall fescue was first introduced as a lawngrass in the 1980s: Initial fescue varieties like Arid and Rebel displayed advantages in lawn density over earlier pasture types. From its very beginning, turf-type tall rescue was promoted as a better drought grass than Kentucky bluegrass. And it was clear to see why: In a moderate drought, Kentucky bluegrass would go dormant brown while tall rescue remained green. It took added research to reveal that rescue was not the drought panacea it was once believed.

The truth lies in the details. Research found that when water is available, tall fescue consumes more gallons than bluegrass. The reason tall fescue stays green longer is its longer roots. Tall fescue's roots draw moisture from a deeper soil profile. Kentucky bluegrass relies instead on dormancy to shut down its leaf growth in a drought, thereby conserving energies for regeneration. Tall fescue does not have the same capacity for revival.

The prolonged Colorado drought of 2002 demonstrated that tall fescue can't recover from severe drought like bluegrass can. Tony Koski, turf specialist at Colorado State University, says he saw many lawns pushed past the point of no return. That summer, Colorado lost more tall fescue lawns from the drought than Kentucky bluegrass.

During extended drought, Kentucky bluegrass lawns stay green with about 1/2-inch of water per week in a single irrigation. Unirrigated, bluegrass turns brown and goes dormant. While dormant, Koski found that Kentucky bluegrass can last three to four weeks without water, so long as traffic is minimized. Tall rescue tolerates drought by maintaining growth as long as water is recharged. Under extreme drought, tall fescue required one inch of water per week to survive--double that for bluegrass.

Therefore, tall fescue may be able to stay green longer than bluegrass during a mild drought, but Kentucky bluegrass sips water more efficiently, and is able to recover from severe drought better than rescue. Once a rescue lawn goes totally brown, it's pretty much dead. Not so with Kentucky bluegrass.

Another drought myth involves fertilization. And, like the last myth, the devil is in the details.

You may have read headlines such as, "It's best to fertilize normally during a drought." And once again, this statement is not true. Dale Devitt and his colleagues at the University of Nevada studied water use at two golf courses and one park located in the Las Vegas suburbs. He found that the golf courses consumed 29 percent more water per acre than the park, which was curious because both were growing bermudagrass overseeded with perennial ryegrass. He traced the disparity to "cultural management in particular fertilizer input."

The average landscape manager uses fertilizer to thicken turf after wear, and to improve its color. But fertilizer has some less-than-desirable side effects, such as stimulating top-growth, succulence and disease--all of which increase water consumption. It is desirable to tailor your fertilizer applications around an expected drought. Before a drought, fertilize normally-only enough to compensate for wear. Then as a drought approaches, slack up on your fertilizer and let your grass "coast" through. Too much fertility at the wrong time can have negative impacts. Keep in mind, however, that after a drought subsides, plants need nutrients to recover from drought damage. For more examples of misconceptions and realties involving drought, please see Table 1 on this page and the next.

Prepare When Beyond Repair

Let's suppose it's now Sept. 1, and despite your valiant efforts battling drought, your turf has lost some of its density and fullness. Not to worry: Drought damage is sometimes less costly to repair than to prevent--especially when you consider the weeks of diligent watering during the summer that might be required.

The primary tool required for drought renovation is a core aerifier. Aerification relieves soil compaction and improves rooting, which by itself drastically benefits drought hardiness. But aerification also provides an opportunity to introduce new seeds into the holes created. Coring and seeding can be done in two steps, or if you find yourself renovating frequently, there are a number of combination tools that slice or core at the same time they incorporate seed--all in one pass.

The key objective in renovation is to get the seed into contact with the soil. Seed remaining on leaves is wasted. Even seeds that make it into the ground have a tough time sprouting, especially if there is mowing and playing on the site while the seeds are trying to grow. The survival rate under these circumstances will be about 20 percent. Thus, it's desirable to double the usual seeding rate to make up for the unsuccessful seed.

Research at Kansas State University has pioneered a scalping technique for renovation that effectively doubles the establishment of new seedlings. A closer-than-normal mowing treatment for four weeks after sowing will restrain the existing grass, so that it doesn't smother the sprouting seedlings. Kansas State recommends using half your normal mowing height while the seedlings are germinating, or whatever height is practical.

After planting, treat the renovated stand like a new seedbed:

* Roll with a weighted packing wheel to firm;

* Allow only light traffic;

* Water frequently; and

* Use a fast-release N-P-K starter fertilizer.

And yes of course, use the drought-tested grass varieties recommended above, so that next year your drought tolerance will be even better. Remember, the most efficient irrigation does not result from computers or fancy electronic timers. It comes from turf managers who choose when each and every irrigation cycle will take place.

Table 1. Misconceptions About Managing Turf in a Drought

Misconceptions                   Reality

"When drought hits, a good       Raising the cutting height when
thing to do is to raise the      drought hits makes matters worse. It
cutting height."                 increases the leaf surface without
                                 increasing rooting. If you're going
                                 to raise your mowing height, the best
                                 time to do it is in the spring before
                                 drought hits. That will encourage
                                 deeper roots.

"Close-cut turf consumes more    Water use is tied to the amount of
water than taller turf."         leaf surface a plant has. Closely
                                 cropped turf has less leaf surface
                                 and thus expends less water per acre
                                 than taller turf. Closely mown turf
                                 also has shallower roots, so it
                                 requires its water on shorter
                                 intervals. But averaged over a
                                 season, short turf consumes fewer
                                 gallons.

"Mowing more often helps         A study at the University of Arizona
conserve water."                 showed that turf mowed six times per
                                 week used 41 percent more water than
                                 turf mowed twice a week. The reason:
                                 Freshly cut leaves evaporate more
                                 water.

"Sharpening your mower blade     Previously it was believed that a
will help reduce water loss      clean cut from a sharp mower would
in a drought."                   reduce water wastage by fewer "split
                                 ends." However, a University of
                                 Nebraska study found that turf cut
                                 with a sharp blade used 33 percent
                                 more water than turf mowed with a
                                 dull blade. The researchers think
                                 the dull blade stunts the turf, in
                                 effect making it less thirsty. They
                                 caution about using a dull blade as
                                 a water conservation tool, since dull
                                 blades reduce visual quality and
                                 increase disease.

"Plant growth regulators         It's true that in addition to
(PGR's) can be used during       reducing mowing, PGR's reduce water
drought."                        consumption by 11 to 29 percent.
                                 But they should be applied before
                                 a drought hits. PGR's freeze turf
                                 in whatever condition it's in, so
                                 they should never be used on
                                 drought-plagued grass.

"It's best to fertilize          It's best to slack up and let your
normally during a drought."      grass "coast" through a drought. Too
                                 much fertility at the wrong time can
                                 have negative effects. But after
                                 a drought subsides, plants need
                                 nutrients to recover from drought
                                 damage

"Switching to an automatic       Making watering easier does not tend
irrigation system and drip       to make people water less. According
nozzles will save water."        to "A Residential End User of Water
                                 Study," conducted in 14 cities in
                                 the United States and Canada by the
                                 American Water Works Association
                                 Research Foundation, homes with
                                 in-ground sprinkler systems used 35
                                 percent more water outdoors than
                                 those without in-ground systems.
                                 Households with automatic timers used
                                 47 percent more water outdoors than
                                 those without timers. Homes with
                                 drip-irrigation systems use 15
                                 percent more water outdoors than
                                 those without. The moral: Regardless
                                 of home or commercial use,
                                 convenience tends to make people
                                 water more.

"Taking out turf and switching   Again, leaf surface area determines
to trees and shrubs will save    water use. Properly maintained turf
water."                          uses less water per acre than trees
                                 and shrubs, according to Dale Devitt
                                 of the University of Nevada. "The
                                 temptation might be to replace
                                 turfgrass with a desert ground cover.
                                 That would be a mistake." Myoporum
                                 and mesquite use more than 30 percent
                                 water than properly maintained
                                 turf. Remarkably, even so-called
                                 low-water-use landscapes (xeriscapes)
                                 used slightly more water outdoors
                                 annually than the standard landscape
                                 group because of the tendency
                                 to over-water.