watering full lawn grass

The Best Time to Water Grass (And Worst Time To Water Your Lawn)

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Written By: Mark Marino, a Massachusetts Core Applicator License holder
and owner/operator of Lawn Phix,

No AI pledge. Authored and reviewed by Mark, not robots. Learn more.

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Aside from proper lawn mowing, the next most important piece to any lawn care guide to a healthy lawn is proper lawn watering. If you follow this guide to proper watering, you’ll avoid shallow root systems, lawn fungus, disease, and oversaturated/dry turf and soil.

What is the best time of day to water grass?

The best time to water grass is in the early morning, completing by 10:00 a.m. This time of day is often much cooler temperatures, resulting in less evaporation, allowing more water to penetrate the soil and infiltrate down to the grassroots.

Newly Planted Grass Seed

To develop deep grassroots, you will want to irrigate deeply but infrequently (more on that below). However, if you’re watering new grass, you want to keep the grass moist. Therefore, watering more frequently throughout the day will ensure that the seed and soil will stay wet. For more information, read our guide to watering grass seed.

Grass Roots

While water lawn timing is important, it’s more about how much water is being put down at each watering. You want to aim for about one inch of water per week in cooler weather months (1″), and one-and-a-half inches of water (1.5″) during the warmer summer months. Therefore, aim for a half-inch of water, 2-3 times per week (0.5″).

You can use the “tuna can method” which the Lawn Care Nut breaks down nicely in the video below. You basically take empty tuna cans and place them in different placements in your lawn, in line of the sprinklers.

  1. Can 2-5 feet away
  2. Can in the middle of the water stream
  3. Can at the end of the water stream

Turn your sprinkler system on and set a timer. When the cans are full, stop your timer and make note of the time. This is the amount of time you need to water each time (2-3 times per week for one-inch of water).

This will ensure deep root systems which are vital to grass health (especially new grass) in the hotter summer months.

Cool Season Grasses

As previously mentioned, watering earlier in the day is the best lawn care advice for watering grass. This time allows the water to soak deep into the soil and further down to the grassroots before the sun begins evaporating it away. So daytime watering should be avoided unless keeping grass seeds wet.

While this time of day (or morning) allows the soil to get a good soaking, the blades of grass won’t be wet for too long. Allowing the plant to dry quickly will decrease the risk of lawn funguses and diseases.

The wrong time is to begin watering your lawn is after 10:00 a.m., or in the afternoon. Once the sun starts heating up the lawn, water evaporates before it gets a chance to make its way beneath the grass blades and into the soil – resulting in a lot of water wasted.

Aside from hot weather months – where you may need to syringe the lawn to cool it down – there will be a lot of water wasted by watering the lawn in mid-day. Most of the water you lay down in the middle of the day will simply evaporate away.

However, watering the lawn too late in the evening can lead to mold and lawn diseases. You want to let the grass blades dry before nightfall. Prolonged exposure to moisture and humidity will greatly increase the risk of lawn fungus.

Leaving water on the lawn at night stimulates the growth of a wide variety of lawn diseases. Of course, watering the grass too late one time will be unlikely to cause an issue, but it’s not worth the risk.

If you can’t water the lawn in the mid-day, the second-best time is early afternoon.

Keep in mind that the more you water, the faster your lawn will grow. Which means you may need to mow the lawn more frequently.

Note: Overwatering can cause your lawn to turn yellow. So be sure to water and irrigate properly.

As long as you water the grass early enough to allow it to dry before nightfall, your lawn will be thankful for the drink!

Lawn Watering FAQs

Can you water the grass in the early evening?

It is best to avoid watering lawns in the evening unless you are watering grass seed. If you water lawns in the evening you are increasing the risk of lawn fungus and diseases.

What time of day is best to water your lawn?

The best time of day to water warm-season grasses and cool-season grasses is before the late morning (10:00 a.m.)

Is there a bad time to water grass?

The worst time to water an established lawn is in the late afternoons and early evenings as the sun is setting. Leaving the grass blades wet or damp for a prolonged period of time will increase the chances of lawn disease.

How many minutes should you water your lawn?

The time is dependent on your irrigation system. Your lawn needs about an inch of water per week (more in the summer). So ideally, you should water the lawn with a half-inch of water, 2-3 times per week. Watering with less water and more frequently will result in a more shallow root system. Be sure to buy the best sprinkler and irrigation heads for your lawn’s square footage.

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Author's Note: this piece has been updated for accuracy since its first publication on

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Author: Mark Marino
My name is Mark Marino, and I am the founder, owner, and operator of Lawn Phix. With a passion for lawn care and turf nutrition for over a decade, I've dedicated countless hours to correcting soil and perfecting lawns. Today, my expertise, backed by formal courses at UMass Extension Pesticide Education, allows me to offer top-tier lawn care services and advice. I am a fully licensed and insured lawn care applicator in Massachusetts, specializing in comprehensive turf nutrition, weed control, and lawn pest control. My license number is AL-0053865. Contact me at [email protected] or +1 (508) 500-8402.

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