Irrigation is the most important component of lawn maintenance. In order for a lawn to thrive, it must have a strong, vigorous root system. Roots need moist and aerated soil to grow properly.
How to water
Water deep and infrequently
Light sprinkling is only beneficial for newly planted turf when the roots are developing in the very top portion of the soil. As turf is established, roots extend deeper into the soil. Light sprinkling will encourage root development only near the soil surface and stunt deeper root growth. Shallow root systems require frequent watering to keep the surface wet, creating an ideal environment for weeds and diseases. Although some grasses have less extensive root systems than others, deep, infrequent watering that allows water to penetrate the top 6 to 8 inches of soil will promote healthy root growth. It also maximizes water-use efficiency and turfgrass quality.
Lawns need uniform coverage to maintain their vigor and a healthy appearance. Brown spots in a lawn are often due to uneven coverage. Use a sprinkler system that can provide this coverage.
Do not overwater
Too much water is not only wasteful but can also increase turf growth, which requires more frequent mowing. Saturated soil can cause poor soil aeration and, as a result, weaken turf making it vulnerable to diseases and invasions of weeds. Not enough water can cause turf to dry out.
Let the soil partially dry out between waterings. Water when the top two inches of soil have dried out. Use an object such as a screwdriver to probe your soil and measure the depth of the moisture.
Avoid runoff and puddling by spacing out, or cycling, irrigations throughout the week until the desired amount is applied. On compacted or heavy clay soils, aerify the soil so that water can easily move into it
When to water
Irrigate only when your lawn needs water
In general, your lawn needs water when the top two inches of soil have dried out. If footprints remain visible after walking on the lawn or if the grass has changed color or has started to wilt, you have withheld too much water.
Irrigate early in the morning
The best times to water are between 2 and 8 in the morning. At these times, water use is most efficient, water loss from evaporation is minimal, and distribution is usually good because of good water pressure and limited wind. During the afternoon, water is wasted due to high evaporation rates. Do not water during the evening or pre-midnight hours because thatch and blades are susceptible to diseases if they are wet during cool nights.
Check with your county for water restrictions
Several counties restrict watering one day of the week or only allow watering on certain days depending on your address.
Schedule your irrigation
Follow this easy-to-use guide to know how much water your lawn needs each month.
See the following publications for more information:
Lawn Watering Guide for California
Managing Lawns on Heavy Soils
Managing Lawns in Shade
Read more about irrigating your established lawn.