Lawns are living plants consisting of over 85% water, therefore they need water to survive. For the majority of the year they will receive sufficient water from the soil and rain, however during dry periods it may be necessary to provide additional water by irrigation. You water your plants and shrubs so why not water your lawn as well?
How you water your lawn depends upon the type of soil that you have. Sandy soils are poor at retaining water, so they should be watered little and often. Whereas clay based soils can hold onto water for longer periods, these soils need to be watered thoroughly and then left to dry for a period. If you water clay soils on a frequent basis this will promote shallow rooting as the roots find the water they need too easily.
If you observe your lawn it will tell you when it needs to be watered, as its moisture reserves become depleted the grass colour will develop a bluish tint and become dull and it will lose its ability to spring back after being walked on. This is the time to water. When it starts to turn straw like it is a sign that it is starting to enter a dormant state through lack of water.
Choosing the time of day to water is important, early morning is perfect, the soil is capable of taking the water and any left in the grass leaf area evaporates as the sun rises. If you water in the evening the grass leaf area remains wet as the night time temperature falls, this can promote fungal disease such as Red Thread or Fusarium.