Many factors influence lawn water requirements in Utah, and no two lawns are exactly alike. The amount of water your lawn requires and receives will determine its overall health, beauty and ability to withstand use and drought. Keep in mind that too much water can ruin a lawn just as fast as too little.
Look at your lawn to determine its water needs. Grass in need of water will have a grey-blue cast to it, rather than a blue-green or green color. Also, footprints will still appear after a half-hour or more on a lawn in need of water, while on well-watered lawns, footprints will completely disappear within minutes.
It is best to water a lawn heavily and infrequently. Light, frequent watering is inefficient and encourages shallow root systems. Excessive watering keeps the turf root system saturated with water and is also harmful. If your sprinkler system is applying water every day, it can lead to disease problems. Keep in mind that sandy soils will need to be watered more often than clay soils; however, less water is needed to wet a sandy soil.
You can also use a soil probe, such as a screwdriver or large spike, to determine how dry your lawn is. If the probe can be pushed into the soil easily, it's probably still moist, but if it takes a lot of pressure to push in, it's time to water.
Each time you water your lawn, apply enough water to moisten as much of the root zone as possible. If the soil is mainly clay, your lawn may require as much as 1 to 1 1/2 inches of water to moisten the root zone. On the other hand, if you have a sandy soil, it can be moistened by as little as 1/2 inch.
The best time to water your lawn is in the early morning’s hours, between 4-7AM. Watering during the day wastes water due to excessive evaporation and can scald the lawn when temperatures are high. Watering in the late afternoon or late morning may be detrimental if it extends the time the lawn s naturally wet from dew. This extended “dew periods” can accelerate disease occurrence.