For optimum healthy growth, lawns need 1.0 to 1.5 inches of water per week throughout the growing season. A common question is, how do I know when I have applied the right amount of water? To answer this question and plan your lawn watering schedule, place a straight sided can under the sprinkler pattern and run the sprinkler or irrigation system for 30 minutes. Measure the amount of water applied in the 30-minute period. A sensible recommendation would be to water for long enough to apply a half inch of water at a time, spreading the 1.5 inches of water to be applied, over three watering periods. Short, frequent watering does not soak up the soil to a depth necessary for deep root development. By applying one half inch of water, three times per week, in lieu of rainfall, you should be delivering adequate water to the necessary depth.