The most common mistake homeowners make when watering the grass is that they water often, but not very deeply. The result of this is that the roots stay near the surface where the water is, instead of going down deep into the soil. The grass becomes dependent on the frequent watering and if you don’t keep up with it, the roots dry out very quickly in the summer heat and drought.
The next most common mistake is watering the lawn deeply, but too often. When the ground is constantly saturated the waterlogged condition will cause thinning and stunting of roots, and rotting in the worst case. During a wet season with a lot of heavy rains, lawns can suffer like this, and the grass becomes weak and off-color, and often ridden with disease.
So how do you water your lawn? For deep and thick roots, you should water the lawn deeply, but infrequently. In heavier clay soils this could be perhaps once a week in the summer. Sandy soils can need twice a week watering.