For continued growth, lawns perform best with an inch of water a week, delivered by 2-3 applications.  We recommend an early morning watering. To determine the length of time to leave your system turned on or to set your sprinklers in one place, set a can or a cup under the main pattern of the spray and time it from the start until it has collected 1/3 to 1/2 inch of water.

The ideal time to water is early morning, when the least amount of moisture will be lost to evaporation.  If this is not possible, the next best choice is to water during the day.  If it is absolutely impossible to water at either of these times, watering in the evening is better than no water at all.  However, note that evening irrigation can often encourage disease and fungi to develop.