Lawn Irrigation Requirements

Lawn Types

• The general rule to supply turf with an inch of water per week, either through rainfall or supplemental watering, needs adjusting for the type of grass you're growing, as well as the season. Two general categories of lawn grasses -- warm and cool season -- have peak growth during summer and fall/spring, respectively. Irrigation needs rise during these growing seasons. Most cool-season grasses are tall fescue varieties, which require irrigation at least weekly, as do warm-season zoysia grasses. Other warm-season grasses, such as Bermuda grass, may grow much more extensive root systems requiring irrigation only every two or three weeks, according to the University of Georgia Extension scientists.

Soil Types

• The amount of water required to irrigate lawn grasses effectively is different for different soil types. Making water available to turf at all times without overwatering can require some careful calculations. Loam and clay soils hold more water than do sandy soils. Thus, sandy soils require more frequent irrigation. Clay soil takes more time to absorb water, however, making it more subject to runoff. The conventional wisdom to irrigate no more often than once a week, therefore, may not be as effective as more frequent watering to replenish soil moisture and prevent overwatering.

Equipment

• Although a simple hose and sprinkler combination can be all you need for irrigating your lawn, calculating the amount of water delivered and setting up and moving the equipment around can be time-consuming. Where rainfall is insufficient, many gardeners install lawn irrigation systems, which may have automatic timers, sensors and other sophisticated technology you can program to deliver precise amounts of water. These time-saving systems cost more to install and require maintenance to keep them functioning properly.

Considerations

• The time of day you water your lawn is important too. Turf specialists often cite early morning as the best time to irrigate. Watering after midnight avoids losing water to heat and wind and allows the grass blades time to dry off before evening, which may help prevent fungal diseases. This timing also avoids peak water use times and creates less interference with other outdoor activities. Other factors that may affect your lawn's irrigation requirements include the amount of sun versus shade that the turf gets, as well as the competition for water from other plantings, such as trees, shrubs and plants.