Proper Irrigation- Not everyone is blessed with sufficient rainfall all year. Where irrigation is necessary, remember the number one principle: shallow, frequent irrigation produces shallow roots. This is true for all grasses. For most grasses, watering deeper, but less frequently will is the number one way of stimulating deeper grass root growth. After watering the soil should be moist at 4 to 6 inches below the surface. These deeper soil depths will remain moist long after the surface has dried. The grass should not be watered again until the blades start to show signs of drought stress. This trains the roots to reach deeper where the ground is more consistently moist.
Please don't think you are harming your grass by waiting to water when grass begins to show signs of drought. This is a long established principle for deeper grass root growth used around the world. Grass has a built-in mechanism to slow water loss during periods of dry, hot weather. To hinder water loss the blades will fold, which shows the lighter blueish green underside. This change in color is a clear signal it is time to water again. A second sign is when you walk across the grass and the blades do not immediately begin to spring back upright. Very hot, dry weather may require more frequent irrigation, but the principle of watering remains the same. You will still water far less than your neighbors who do not know about proper irrigation techniques and will have better grass root growth. Cooler weather will require less water.
During hot weather, it is best to water early in the morning. Setting your timer so the water comes on at 4:00 or 5:00 am is good. Try not to water in the evening or at dark where the ground remains extra wet all night. Many diseases need prolonged surface soil moisture to get started. See our section on grass diseases for more information.
There are some exceptions, however. Sandy soil does not retain water well, so deep water may not be helpful. For extremely sandy soil, the only option is to add organic matter to the soil for better water retention or water more frequently. The grass will tell you when it is time for more water.