It’s one of the most common questions we get. “How often and how long should I water my lawn?”
The short answer is to water in the morning at least a half inch twice a week, but to keep your grass healthy, you need to know more. The following guidelines will help you decide what’s right for your lawn.
Start with half an inch twice per week (including rain) as a good rule of thumb for watering frequency, but also keep a constant eye on your lawn. It will tell you if and when it needs more frequent watering.
Thirsty grass will look stressed. The color will turn a dull blue-green, and the blades will often curl or fold. If you walk across the grass and your footprints remain visible, that’s another sign of water-deprived grass.
When you see any of these signs, water the stressed area, regardless of your normal watering schedule.
Keep in mind that deeper, less frequent watering results in deeper roots and makes more nutrients and water available for your grass to grow and thrive. Since soil dries from the surface down, grass with deeper roots is more drought resistant. Deeper watering also helps deter many weeds, especially crabgrass.
To encourage deeper roots, the University of Georgia (UGA) Extension Service recommends soaking your lawn to a depth of six to eight inches. The amount of water needed to reach six to eight inches will depend on the output of your sprinkler, as well as the type of soil in your yard. Sandy soil may reach that depth with only a half inch of water, whereas a clay yard may need as much as 1.75 inches.
How to Test Moisture Depth in Your Yard
To test the depth of moisture in your yard, push a spade or stake into the ground two to four hours after watering, and measure how far down the soil is moist. Generally the spade will move more easily in damp soil, so you’ll likely feel when you hit dry dirt. If the earth is dry less than six inches down, increase the watering time.
Watch for Run-Off
Watch for run-off. Clay soil needs more time to absorb water. You may need to turn off the sprinkler intermittently to give the water a chance to soak into the ground.
If you have a sprinkler system, attach a rain gauge so you don’t water an already wet lawn. Watering too much can actually cause damage to your grass by inviting algae, root rot, and other issues.
Periodically check shaded areas to make sure they do not get too much water, since they may need less frequent watering than sunbathed areas. Also watch sprinklers to avoid too much overlap.
Time of Day
According to the UGA Extension Service, 50 percent more water is lost to evaporation from wind and heat when watering midday. Temperature and wind speeds are often lowest just before sunrise, making it the optimal time for irrigating.
Research also shows that watering just before sunrise while the grass is still wet with dew helps ward off common lawn diseases. Of course the time for sunrise changes continually, so check sunrise times every two or three weeks and adjust your watering timers accordingly.
Lay of the Land
Conditions of your yard, including the type and variety of grass, the quality of soil, and the amount of shade, all directly affect how often and how much you need to water your lawn.
For example, Zoysia tends to need watering more often than most varieties of Bermuda, and grass grown in sandy soil needs more frequent watering than the same variety grown in clay soil. Shady areas, however, hold onto moisture longer and may need less frequent watering than areas in full sun. Knowing your grass type and the environment where it’s growing will help you avoid damage from too much or too little water.
Keep in mind that ever-changing environmental conditions like wind, heat and hours of sunshine can increase your lawn’s need for water, and extended dry spells can also make lawns thirstier.
Thatch, a build-up of dead grass between the green grass blades and the soil, and frequent fertilizing are two additional factors that can increase a lawn’s water requirements.
New grass needs more water than existing lawns. If you install sod, stop between pallets to water the freshly laid grass to keep it moist. Damage can be done if you wait until the project is finished to start watering.
In the summer, newly installed sod may require a deep soaking twice per day, once in the morning and once in the evening. Once the lawn is established, usually in two to three weeks, you can follow watering guidelines for existing lawns.
Unless you irrigate from a well or other private source, watering the lawn can be an expensive enterprise, especially during the heat of summer. Watering efficiently will save you money in the long run, and will also help during dry spells when communities often restrict water usage. The goal of any successful watering plan is to use as little irrigation as possible while keeping your grass beautiful and healthy.