How often a lawn should be watered depends on local rainfall levels, soil content and the type of grass planted. Some species are drought resistant and others have deeper roots, which would require less water. Other species have shallow roots or are planted in compacted soil, which require more water.
When to Water
The early morning is the best time to water, say lawn experts Nick Christians and Ashton Ritchie, because the lawn has all day to dry and less wind to disrupt the spray from the target zone. Avoid watering overnight in moderate climates because this practice can lead to disease. An exception to this would be dry regions with low humidity because overnight watering is less likely to evaporate.
Footprints in the grass and discoloration are signals that it is time to water the lawn. Dry spots, too, are an indication that the grass is dry.
How Much Water
Christians and Ritchie, in their book "Lawns," say that the minimum amount of water a lawn needs, in most instances, is 1 inch a week. This recommendation is for normal lawns with loamy soil and deep roots in an area with normal rainfall. For these typical, normal lawns, Christians and Ritchie recommend either deep and infrequent watering where the lawn gets the 1 inch all at once, water a little at a time everyday, or water twice a week for half an inch at a time. Watering more at once is the preferred way as the roots grow deeper and easier, and healthy roots are the key to a healthy lawn.
Soil Type
If the soil type is not ideal, then the frequency of watering changes. For example, water does not penetrate clay soils easily and if the water is left on too long, puddles form. Kristen Hampshire in her book, "Landscaping and Lawn Care," recommends watering clay soil more frequently for shorter periods of time to let the water work into the roots.
In sandy soil, water evaporates quickly and doesn't make it down to the roots. Even watering more won't ensure that the water makes it down to the roots. The best bet, Hampshire says, is to add either organic or man-made material to sandy soil to stabilize it. This filler is called an amendment and includes peat moss, wood chips, sawdust and straw, to name a few.
Grass Type
There are two types of grass, warm season and cool season. Within these two types, the amount of water needed varies from grass to grass. For instance, St. Augustine grass needs more water than bermuda grass, even though both are suited for Florida, says Christians and Ritchie. The best bet is to research grasses based on region and then on drought resistance. According to Christians and Ritchie, these types are listed from those needing least water to the most: buffalo grass, bermuda grass, zoysia grass, centipede grass, bahia grass, St. Augustine grass, fescues, Kentucky bluegrass, perennial ryegrass and bent grass.
Methods of Watering
There are many ways to water the lawn, sprinklers---oscillating and pulsating--- soaking hoses and irrigation systems are a few. Sprinklers are the most cost-effective way to water but the most inefficient because of the tendency to overwater due to lack of uniformity in the sprinkler head. There are timers available that allow users to program when they run. Soaking hoses are best used in narrow and small areas such as pathways or flowerbeds. Irrigation systems, or underground sprinklers, operate on timers and can save money by offsetting the cost of a system versus overwatering.
Tags: Christians Ritchie, water lawn, time water, amount water, Augustine grass, bermuda grass