Soil can dry out very quickly on sunny or windy days. So during the first few weeks of watering, you need to concentrate on keeping the lawn surface moist. This is best accomplished by frequent light waterings, especially on hot, sunny days. Areas of the lawn in full sun need watered more often than partially shaded areas. Lawn edges and curb areas are very easy to miss.
Slopes always dry out faster than level areas.
Morning is the best, even if it is just before sunrise. Late evening is the time to avoid watering a lawn if possible. Turfgrass watered in the evening tends to stay wet all night, providing an ideal environment for fungus disease. Begin mowing the lawn as soon as it needs mowing. Bagging the clippings is usually best for a new lawn.