Determining How Long You Should Run Your Sprinklers

Learn how long you should run your sprinklers with our guide. Hint: Most people are either underwatering or overwatering.

Most people are woefully misinformed when it comes to our lawns.

74% of Americans believe they know how to care for their lawn each season.  I think we are just proud people because 35% of those same Americans freely admitted they did not know how to water a lawn properly.  

And that doesn’t include the folks that faked their way through the questionnaire and don’t know the first thing about proper lawn irrigation. 

People don’t like admitting when we are out of our depth.

Today, you will no longer be out of your depth when it comes to your sprinkler system. In this article you will learn how to ensure your lawn is properly irrigated.

How Often to Run the Sprinklers

There are a couple of factors used to determine how often you should water your lawn. 

The first is to determine how much water your lawn is already receiving per week through rainfall.  Use a rain gauge to determine if your lawn’s watering needs are met naturally or not.  If the rain gauge holds between 1 inch and 1.5 inches of water after a week, then you don’t need to water the grass.

The second is the grass type you have growing on your lawn.  Warm-season or cool-season grass?

Cool-season grasses like Kentucky bluegrass and perennial ryegrass require more water than warm-season grasses like bermudagrass and bahiagrass

During the growing season, watering recommendations for cool-season grasses are to water every 2 to 3 days.  Watering recommendations for warm-season grasses are to water every 3 to 4 days during the growing season.

Whether you water your lawn in the winter months is entirely dependent on the climate in your area. 

If you receive a significant amount of snow, then you can turn off the sprinklers until spring.  In these areas, the precipitation of irregular rainfall and snow should be enough to supply your grass with 1 inch to 1.5 inches of water per week through the colder months of the year.

For warmer climates, remember the phrase, “If you’re still mowing, then your lawn is growing.”  If this describes you, you need to keep watering the grass until mowing is no longer required.  Then you can count on Mother Nature to take care of your lawn’s irrigation needs until spring.

How Long to Run Sprinklers

Both warm-season and cool-season grasses need between 1 inch and 1.5 inches of water per week to maintain ideal soil conditions for the grass to flourish.

Generally speaking, it takes between 20 and 30 minutes of watering your lawn three times per week using an above-ground sprinkler type.  This will supply a sufficient amount of water for what the lawn needs to maintain optimal conditions for grass’ root systems.

Some in-ground types of sprinklers need to water your lawn for an hour or more to provide the grass blades and grass roots enough water. 

Are You Running the Sprinklers Enough

Calculating the Proper Amount With a Flow Timer or Water Timer

These timers measure the flow of water in gallons of water your lawn is receiving.  To calculate the number of gallons needed for 1 inch of water, multiply the total square footage of your lawn by .62 gallons.  The total will give you the number of gallons needed to cover your lawn with one inch of water.

If you are watering your lawn more than one time a week, divide that number of gallons by the number of days you plan to water your lawn.  This will give you the correct number of gallons needed each time you run the sprinklers.  Program the timer to run the sprinklers for the specified number of gallons. 

Tuna Can Method

Measure the depth of the water each area of your lawn is receiving by placing empty tuna cans or other containers flat onto the ground in the areas you will be watering.  Run the sprinklers until the water rises to a specified depth in the tuna cans or containers.  The number of days you plan on watering your lawn will determine the necessary height of the water in the tuna can.

The corresponding depths follow here:

  • Every 4 days – ½” to ¾”
  • Every 3 days – ⅓” to ½”
  • Every 2 days – ¼” to ⅜”

A good way to tell if your lawn is receiving enough water is to take a standard screwdriver and push it into the soil.  If you can depress it to the handle of the screwdriver, you are watering an appropriate amount.  If you cannot depress it to the hilt, then you’ve got a problem.

Best Time to Run the Sprinklers

Ideally, the best time to water your lawn is after 8 a.m and before 10 a.m.  This will keep the earth cooler during the hottest parts of the day so the vegetation won’t scorch.  It will also allow time for the grass to dry before nightfall. 

If this is not practical, you can water your lawn in the late afternoon.  The sun is still out, and the water will have a chance to dry from the grass and absorb into the soil.

It is ill-advised to water your lawn in early or mid-afternoon.  The heat of the day evaporates the water before it has had an opportunity to absorb deeply into the soil.

Avoid watering in the evening entirely.  Watering once the sun has gone down will keep your lawn wet through the night and leave it prone to disease and fungus.

How to Run the Sprinklers on Different Soil Types

Water soaks into different soil types at different rates to nourish the grass roots contained therein.

Sandy soil absorbs water the fastest at a rate of 4 inches of water per hour.  Clay soil, on the other hand, absorbs 0.2 inches of water every five hours.  The most efficient soil absorption ratio belongs to sandy loam as it absorbs one inch of water per hour.

So, you should determine what type of soil you have on your lawn before irrigating.  By heavily watering clay soil on your lawn, you may inadvertently wind up drowning the plants on the surface. 

Determine how quickly you can water your lawn based on how long it takes for the water to absorb into the ground.

So there you have it.  Now you know the lawn care basics of watering your lawn.  Apply this knowledge and watch your lawn flourish and your water bill shrink.

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Happy Planting!

About the author: Jeffrey Douglas is a horticultural hobbyist that loves everything related to plants and gardening. He specializes in gardens and houseplants.

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