Usually, here in Central Ohio, we have plenty of rainfall to keep a lawn in good condition. However, there are times when rainfall becomes erratic and your lawn can turn brown without providing supplemental watering.
Our lawns require about 1″ of water per week before they start going into dormancy. Obviously, if your lawn doesn’t get 1″ of water for 1 week, it’s not going to die or turn brown. However, if that lack of water starts to expand to 3 weeks, then the lawn will go dormant. Dormancy is a lawns way of surviving till the water returns. A lawn can survive in dormancy for many weeks before it dies. Although a dormant lawn looks bad, it will return in most cases except in extreme cases where adequate water is absent for more than a month (which happens rarely in Central Ohio).
It is best to water the lawn until runoff just begins, and avoid watering each day. The number of times to water each week depends on how long the irrigation system can run before water just starts to puddle or run off the soil surface laterally. For example, if your lawn needs 40 minutes of irrigation each week, but runoff begins after 20 minutes, then water twice a week for 20 minutes.
In cases where soil takes up water so slowly that runoff occurs before 10 minutes, water cycling may be necessary. To cycle, irrigate until runoff just begins, turn the system off, and repeat the process in 30 minutes before the soil surface dries out. Several cycles per day may be necessary to apply the desired amount of water.
The best time to water is early in the morning when evaporation rates are lowest and water pressure is at its peak. Irrigating in the afternoon is wasteful because of higher evaporation rates, and prolonged damp conditions in the evening may encourage disease development.
Irrigation requirements change from month to month and may not be needed at all if it has rained. Reset your sprinkler system to meet your lawn’s changing irrigation needs.