How and When to Water
Make sure to get even water distribution.
Generally a well designed in-ground sprinkler system should take care of this issue for you, but if you’re using a traditional lawn sprinkler you should make sure to monitor the volume and coverage that it provides. Placing flat-sided objects around the yard such as an ice cream pail or bucket can help measure water application rates. You’ll want to avoid over watering or flooding areas, or missing other spots. If you’re lawn has a steep slope or heavy clay soil you may want to water in shorter more frequent applications to avoid excessive runoff.
When you water is crucial.
Watering early in the day when lawns are normally wet from dew is the ideal time to water in most cases. You should try and avoid midday watering due to the evaporation resulting from midday heat, as well as at night due to increased chances of diseases and fungus taking hold. However, the exception to thus rule is when you are in extremely hot weather and nighttime temperatures stay above 68º. When this is the case watering in the late afternoon or early evening can actually be optimal for your grass as it reduces the amount of evaporation that takes place during very hot days, allowing more water to reach the roots.