I know we have had good rain this year, but the hot, dry days of summer have arrived. Keeping our lawns green in August can be a challenge even with a good irrigation system. Watering is one of the basic elements of lawn maintenance and often one of the costliest.
Soil type, grass species and turf management influence the amount of supplemental water and the watering frequency required for lawns.
Sandy, coarse-textured soils absorb water at a much faster rate than finer textured soils, but retain less moisture. Therefore, sandy soils will require more frequent applications of water at lighter rates. Clay soils retain more moisture and should require less frequent watering. Clay soils absorb water very slowly so application rates should be slower and extended over a longer period.
Grass species and management practices largely determine the amount of supplemental water required for lawns. Bermuda grass will go dormant during a drought and recover fairly well if it is not an extended drought. Other grasses such as centipede and St. Augustine do not possess this drought tolerance. Significant turf grass loss can occur if these species are allowed to experience severe drought stress for an extended period of time.
During hot, dry conditions raise mowing heights to reduce water needs. Mow St. Augustine grass at 3 inches during dry weather. Do not mow Bermuda grass higher than 2 inches.
Timely applications of water are required for effective and efficient water use. Apply water just as the grass begins to discolor and wilt. Most grasses turn dark and dull and the leaf blades begin to fold or roll when the grass goes into water stress. Grass under water stress also shows tracks after someone walks across the lawn.
The time of day also influences the effectiveness of watering. Early morning is considered the best time to water. Early morning watering helps to wash dew off the leaves which reduces the incidence of diseases. Later afternoon is considered the worst time to water because the grass remains wet through the night and is more susceptible to diseases.
How much water to apply to a home lawn can be very confusing for a homeowner with an automatic irrigation system. Unfortunately, grasses do not utilize water on a set scheduled. Apply enough water to a lawn to wet the top 4 to 6 inches of soil. Light, frequent applications of water produce weak, shallow-rooted turf highly susceptible to stress. The application of 1 inch of water will adequately wet most soils. The time required to wet the soil to this depth depends on the type of sprinkler used, the water pressure available and the rate at which the water moves into the soil. Sloping sites require light watering at frequent intervals.
The key to success in watering home lawns is to condition the grass to get by on as little supplemental water as possible. The use of good turf management practices will develop a deep-rooted turf which can withstand drought conditions. These management practices are listed below:
• Fertilize according to soil test results
• Mow at proper heights recommended for different grass species and varieties.
• Water infrequently and deeply only when the grass needs it (usually 1-1.5 inches per week)
• Turn automatic sprinklers off preset schedule. Go out and manually turn sprinkler on when it is time to irrigate.
• Always have shape lawnmower blades.