How Long to Set an Irrigation Timer

Last Updated on October 2, 2023 by Kyle Whitley

When you are setting up your sprinkler system, it is important to determine how long to run your sprinkler system.  Let’s take a look at how long to set an irrigation timer for your lawn.

Let’s face it watering your lawn is not an inexpensive task.  It is best to know how much and how often you should water your lawn not to waste water and money.

When and How Often Should You Water

The first step when watering your lawn is determining how much water you need. This will depend on several factors, including weather conditions, type of grass, size of the area being watered, etc.

For example, if you live in an arid climate with hot summers and cold winters, you’ll want to water less differently than someone who lives in a humid region where temperatures fluctuate little throughout the year. A good rule of thumb is to apply 1 inch to 1.5 inches of water per week to each square foot of turfgrass.

When to Water Your Lawn

Your lawn needs more specific care than you would think since it can appear like you can go out to water it anytime during the day. If you want your grass to grow well, you should water in the morning when winds are calmer, and the water can sink into the soil.

You should do this before 10 AM in the morning if at all possible so that the grass has time to dry before full sun exposure later in the day. If you must water in the evening, do it between 4 and 6 PM to get the grass blades dry before nightfall. If you water in the late afternoon and evening, your lawn will become more prone to disease.

How Often to Water Your Lawn

A good rule of thumb is to apply about one inch of water every week.  How often you water depends on the output of your sprinkler system.

To get that 1 to 1.5 inches of water, you can water on multiple days in shorter sessions or water more heavily in a single longer session.

The key is to remember not to overwater the lawn, which can cause runoff.  The soil can only absorb some much water an hour.  The soil, in general, can only absorb .25 inches of water an hour.

Check the Moisture of the Soil: The Easy Way

The best way to determine whether or not your soil needs more moisture is to test the soil’s moisture while the sprinkler system is running.  It is easy to do this with your average screwdriver.  Test the soil moisture with the screwdriver after the sprinkler system has run for 15 minutes.

Test the soil by pushing the screwdriver into the ground.  Note the depth and time.  Continue the process every 15 minutes until you can push the screwdriver 6 inches into the ground.

The Old Tuna Can Trick

Measure how long it will take to collect up to 1.5 inches of water from a clean, empty tuna can by placing it in different spots around the lawn. The average time it takes to fill cans should be used since the sprinkler coverage patterns may vary around the lawn.

Basically, measure the amount of water in each can and determine the average.  That average will give a good idea of how much water your sprinkler system can put out during a given period of time.

Let’s Do the Math: Calculating How Long to Run Your Sprinklers

Divide your lawn’s weekly water needs by your sprinkler’s hourly water output to find out how long your sprinkler runs each week. If your sprinkler output is 1.5 inches per hour, you would need to run it for a little less than an hour a week, or roughly 40 minutes on average.

Based on the lawn’s ability to absorb approximately .25 inches of water per hour,  in this scenario, you would run your sprinkler system for 10 minutes at a time to not overwater your lawn in a single sprinkler cycle.

If you need to water more, have the sprinkler system or irrigation timer set up to run multiple times to give the lawn time to absorb the water into the soil between waterings.

Smart Irrigation with Smart Irrigation Controllers and Timers

If you are still confused about how long to set an irrigation timer, then you might want to consider a smart irrigation timer or smart sprinkler system.  Irrigation controllers can adjust the water used to different kinds of landscapes. Information about soil type, plant type, slope, and weather data helps to apply the correct amount of water to the lawn or landscape.

I personally use a smart irrigation controller from Orbit, which controls the watering of my three zone sprinkler system based on the current weather, soil, and slope of my lawn.

Rain Sensors

A rain sensor is usually used for precipitation detection and wired to your controller. It shuts down any regular irrigation if a certain amount of water is detected.  This will keep you from wasting water when normal rainfall is occurring.

Soil Sensors

A soil sensor will detect the moisture in the ground and can be used to know the amount of water around the root system. The soil moisture sensor will shut down the irrigation system if the soil is at the correct moisture.

Watering Different Lawn Types

Several factors are involved in how long to water lawns and how to care for them, such as the season and the type of grass you are growing. It’s important to pay attention to the types of grass that you are growing, as each has its own watering and care needs. Setting a schedule that will give thirsty lawns the perfect amount of water all season is elementary once you know how much to water in a specific lawn type.

Warm-Season Grasses

Bermuda and Zoysia are examples of warm season grasses.  The air temperature above 80 degrees creates optimal conditions for the growth of warm-season grasses. When daytime temperatures start to drop, they slow down but still need hydration to remain healthy.

As long as they are growing, continue to give them water and mow it at least once a week. It’s not the ideal time to fertilize warm season lawns in the fall. The active growing season begins in the spring, and you should fertilize them then. Remember to water fertilizer in thoroughly.

Cool Season Grasses