Proper irrigation is the first step in conditioning a lawn for drought. Many people rely on their automatic sprinkler systems to apply small amounts of water several times weekly to their lawn. This practice promotes a lawn that requires more water and one that cannot withstand drought stress.
The following is provided by Dr. Laurie Trenholm, UF/IFAS Extension Turfgrass Specialist.
To develop a deep root system, lawns should only be watered when the first signs of wilt occur. Spots in the lawn that turn bluish-gray, footprints that remain in the grass long after being made and many leaf blades folded in half length-wise are indications that the lawn needs water. Apply only enough water to wet the soil in the rootzone. For Florida’s sandy soils, 3/4 inch of water is sufficient. The next irrigation should be withheld until signs of wilt occur again. It may take up to 6 weeks to condition a lawn to survive several days or more without wilting between irrigations or rainfalls. During this time the root system is growing deeper. In time, the lawn will establish a more uniform appearance with less thatch and a deeper root system.
Proper mowing is essential for a drought-resistant lawn, too. Use of the highest cutting height on the mower will facilitate turfgrass drought-conditioning. The higher the mowing height, the deeper and more extensive the root system will be. Mowing should be done often enough to minimize the shock of cutting. Never mow off more than one-third the height of the leaf blade at any one time. Adjust frequency of mowing to the growth of the turf. Keep mower blades sharp. A leaf cut by a sharp blade will lose less water than a leaf blade shredded by a dull mower blade.
Correct fertilization can enhance drought tolerance of lawns. All of the drought conditioning accomplished by proper irrigation and mowing practices can be eliminated by excessive nitrogen fertilization. Drought conditioning can only be accomplished by applying just enough nitrogen to obtain a small but continuous amount of growth. Potassium fertilization, however, can help turfgrasses increase their tolerance to stresses, including drought. Potassium promotes increased root growth and thicker cell walls. Soil testing is helpful in monitoring nutrient levels and determining fertility requirements.
High-quality turf cannot be maintained without supplemental irrigation, although a lower-quality turf may persist. In landscapes where poor-quality turf may detract from the design, alternatives to turf should be considered. Mulched bed or groundcovers may be more suitable. Plant materials that do not require supplemental irrigation should be chosen.
Contact your County’s University of Florida Extension Office for more information.