Summary

  • Watering your lawn in the morning, from 6 a.m. to 8 a.m., helps prevent water wastage through evaporation and promotes even watering due to less wind disruption.
  • The length of time to water your lawn can be determined through a can test, where you measure how long it takes for an empty can to fill with 1.5 inches of water.
  • Different types of grass have different water requirements, with warm-season grasses needing deep, infrequent watering and cool-season grasses needing more frequent watering due to their less extensive root systems.

Running your lawn sprinklers is an essential lawn management practice that keeps your outdoors green. Water helps grass fight weeds, maintain vigorous growth, promote nutrient uptake, and enhance root growth. However, watering your lawn at the wrong time of the day can negatively impact its health.

Therefore, you need to find the best time to run your sprinklers. It's the only way your lawn grass will stand out in your neighborhood!

The Best Time to Run Your Sprinklers

Run your sprinklers when there is less wind and evaporation

According to the University of Missouri Extension, the best time to water your lawn is from 6 a.m. to 8 a.m. When you water your lawn in the morning, you won't lose as much water through evaporation as you would during hotter times of the day. Also, there is less disruption of the water pattern by the wind, which promotes even watering.

When not to water your lawn

Reasons

Midday

High water evaporation

At night

Promotes lawn diseases

Watering your lawn in the morning has some advantages:

  • Prevents water wastage through evaporation
  • Promotes even watering because there is no wind to disrupt water patterns

Watering your lawn at night keeps your grass wet for at least 12 hours, which creates a perfect environment for fungal diseases that thrive in damp foliage. Examples include pythium bright, powdery mildew, and leaf spot lawn diseases.

How Long You Should Water Your Lawn

Run your sprinklers for a predetermined period of time

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Knowing the best time to water your lawn is beneficial. However, it's also crucial to grasp how long it will take to water your grass sufficiently. The amount of water your lawn needs may depend on the type of grass, season, and whether it's a new lawn. During winter, for example, you only need to water about an inch per week. However, during the other seasons, water your lawn 1 to 1½ inches weekly.

According to New Mexico State University, College of Agricultural, Consumer, and Environmental Sciences, homeowners can do a "can test" and determine how long it will take to water their lawn. With this data, you'll avoid incidences of under-watering or over-watering.

To perform a can test:

  • Place an empty can in an area watered by the sprinkler
  • Run your sprinkler
  • Track how long it takes for the can to fill 1½ inches of water
  • The length of time it takes to fill is the period you should water your lawn

To calculate your lawn irrigation time using the sprinkler's flow rate (you can get your sprinkler's flow rate from the manufacturer), multiply your lawn's square footage by 0.62 (an inch of water per square foot a sprinkler head covers). Divide this result by your sprinkler's flow rate.

Watering a Newly Planted Grass Lawn

Run lawn sprinklers twice a day to support recently planted grass

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Understanding the watering requirements of a newly planted lawn is essential in establishing new yards. Unlike established lawns, freshly planted grass requires daily watering, especially during dry conditions.

As the grass grows, reduce the watering frequency to once a week. However, keeping the soil moist is necessary to encourage root development. Maintain soil moisture to a depth of 1 to 2 inches at any given time.

Established Lawn

New Lawn

Water once or twice a week

Water every day

Provide 1½ inches of water every week

Maintain moist soil to a depth of 1 to 2 inches

Watering Warm and Cool Season Grasses

Run your lawn sprinkler based on the type of grass on your lawn

According to the University of California, Agriculture & Natural Resources, cool and warm-season grasses have different water requirements. Warm-season grasses thrive with deep, infrequent watering. Aim for 1 inch of water with one or two weekly watering sessions.

Common warm-season grasses include:

  • Bahia grass
  • St. Augustine grass
  • Zoysia lawns

Cool-season grasses need more frequent watering due to their less extensive root systems according to Kansas State University. Water your grass three times a week and keep your soil moist at 1 to 1½ inches of water per week. Some examples of cool-season grasses include:

  • Kentucky bluegrass
  • Tall fescue
  • Perennial ryegrass

There are different water requirements for warm- and cool-season grasses.

Warm-season grass

Cool-season grass

Water one to two times a week

Water three times a week

1 inch of water every week

1 to 1½ inches of water per week

How to Tell Your Lawn Needs Water

Run your lawn sprinkler when you notice slow growth on your grass

Understanding when and how to run your lawn sprinkler is a game changer in outdoor grass management and helps you know when to water your grass. However, being aware of some common signs that your lawn needs watering is beneficial.

  • Slow growth on your lawn
  • A grayish cast on your lawn
  • Dry and sandy soils to the touch
  • Visible footprints (grass doesn't bounce back after walking on it)

If your grass lawn has these signs, water may not be the only problem. Your yard could be suffering from a nutrient deficiency or a fungal disease attack.

Run Your Sprinklers at the Right Time

Learning how to run your lawn sprinklers at the right time to keep your lawn green

Watering your lawn is a primary outdoor grass management practice that every other homeowner understands. However, knowing how and when to run your sprinklers is much better. You'll keep your lawn healthy, save water, and reduce fungal diseases by watering at the right time.

Share this information with your friends and tell them the best time to run their sprinklers.