How Long to Water Grass—and How Often—for a Healthy Lawn

Signs Your Lawn Needs Watering

How do you know how often and how long to water grass? It’s time for watering when you see these three signs:

Curled-up leaf blades in the evening. Wilting blades during the highest heat of midday sun is not a good indicator; check the condition of the leaves in the evening instead.
Blue-gray blade color instead of green
Footprints or lawn mower tire tracks remain visible long after being made

Basic Watering Rules

Water Deeply

Turf grass can turn brown and go dormant, but that does not mean it is dead. If you live in an area with water restrictions, it’s a good idea to let your grass go dormant. Grass can stay alive for three to four weeks without rain. If you decide to water dormant grass during a long dry period, water it long enough to moisten the top 5 inches of soil. This keeps grass alive, but there may not be enough water for the lawn to green up.

Let Soil Dry Between Waterings

Always allow the soil to dry out, and wait until the blades wilt before turning on your lawn irrigation system again.

Do Not Water Daily

Watering daily wastes water and clogs the air spaces between soil particles that the roots need. When grass roots can’t breathe or grow, or grass blades are wet for longer than 14 hours, they become vulnerable to various diseases and pests.

Water During the Dew Period

The best time to water the lawn is generally between 4 a.m. and 8 a.m., or during your lawn’s natural dew period, to reduce the amount of water lost to evaporation. Double-check the natural dew period in your area to be sure you’re watering at the right time of day.

How Much Water Does Your Lawn Need

Generally, it’s best to water your lawn deeply but less frequently. This practice encourages turfgrass to develop deep roots that sustain it better through periods of drought. At each watering, apply about 1 inch of water.

Measuring Water From Sprinklers

You can determine how long it takes your water sprinkler to distribute 1 inch of water by placing several shallow containers on your lawn while running the sprinkler for 30 minutes. Measure the depth of the water in the containers. The average depth times two is the number of inches of water per hour your water sprinkler system emits; this simple calculation will tell you how long it takes your sprinkler to distribute 1 inch of water, so you know how long to run it to get that just-right amount of water.

Other Factors to Consider

The length and frequency of watering grass, as well as the timing, depend on several factors, including:

Grass Type

The watering needs of warm-season grasses like Bermudagrass and Zoysiagrass are different from those of cool-season grasses like Fescue, which goes dormant in summer heat.

Soil Quality

A healthy lawn needs good soil, just like a garden. Your lawn soil should be well amended with at least 4 to 5 percent organic matter, such as compost from plant waste or animal manure from cows, chickens, or horses. If your lawn struggles despite your best efforts, test your soil. Poor or dry soil may require more frequent watering.

Weather

Cool, wet weather gives you a break from lawn irrigation tasks. If your sprinkler system is set on an automatic timer, check it frequently so you can turn it off after a stretch of rainy days.

Grass Height

Grass cut at 3 inches tall retains more water than grass cut at 2 inches. Keeping your grass cut to the proper height can reduce how often you need to water and how much water your lawn needs. During hot or dry weather, mow the grass higher to reduce stress. Longer blades encourage deeper roots to absorb more water.