When irrigating turfgrass the general rule of thumb is to water deeply but infrequently. Deep watering promotes the development of deep extensive root systems. Sprinklers are the best way to water lawns. The amount of water applied may be estimated by placing several straight-sided cans in the spray pattern and then measuring the amount of water in the cans with a ruler. The best time to water a lawn is early morning.
Winds are generally light and temperatures cool so little water is lost through evaporation.
Watering at midday is less efficient because evaporation is often high and strong winds may cause uneven water distribution. Strong midday winds may also carry the water onto driveways or streets and waste considerable amounts of water. Watering the lawn in the evening or at night may increase disease problems. Hot, dry summer weather does stress cool season turfgrasses. Proper care of the lawn during this period helps to maintain a healthy, good quality turf.