Most summers in Indiana will call for irrigation of the lawn in order for it to maintain its color. Water only as needed when it first starts to show signs of water stress. This could be a blue-gray color of the grass, or if footsteps in the lawn remain visible after walking across it. Your lawn should be irrigated less frequent for longer periods of time as this will encourage the grass roots to go deeper after the water.
Shallow watering will create shallow root systems. The lawn usually needs 1.5″-2″ weekly to maintain color, but every lawn reacts differently. Generally speaking watering every 3 days or so for about an hour per zone should get you the amount of water needed for the lawn. It is best to measure the water your lawn is getting with a rain gauge which is available at any local hardware store.
Time of Day?
Early morning is a much better time to mow your lawn than in the evening. If you do not water enough to keep your lawn green during periods of heat and drought it is important to remember that the lawn still requires 1″ of water every couple of weeks to prevent die back of the turf. You can have a healthy brown lawn, but it still needs moisture for respiration.