Watering your lawn is much more than just running your sprinklers for a couple of hours each week.
When you get to the root of the matter, there are a number of factors to keep in mind. This includes the grass type, sprinkler water output, your lawn’s weekly watering needs, soil type and weather conditions.
The answer to how long you should sprinkle your lawn varies. Typically, most lawns need 1-1½ inches of water each week. This roughly translates to 20-minute watering sessions twice a week. But don’t forget to keep an eye on the weather. Cut down on watering during rainy weeks and increase it during sunny weeks.
Join us as we take a stroll through your lawn and explore its weekly watering needs.
Image credit: @hoselinkusa
How long should I leave the sprinkler on my lawn?
Watering your lawn is a tricky business. Too much water and your grass and water bill will suffer, too little and you run the risk of killing your lawn.
Don’t worry. The following steps will help you to sprinkle your lawn with precision. In other words, simply follow them for a healthier, greener lawn year-round.
1. Understand your lawn’s weekly watering needs
Most lawns need an average of 1 to 1½ inches of water each week. That said, specific watering needs vary by grass type. So, the first step is to identify your lawn grass.
Some of the most common types of grass in UK lawns include dwarf ryegrass, annual meadow grass, red fescue, and common bent.
Dwarf ryegrass has narrow, blade-like leaves and red fescue can be easily identified by its fine, deep green blades. Both these grasses like occasional watering, not more than 1 inch per week.
On the other hand, annual meadow grass and common bent enjoy deep watering, about 1½ inches each week. They both feature low-growing, carpet-like sod.
2. Figure out the water output of your sprinkler
Next, measure the water output of your sprinkler. This will help you calculate how much water your sprinkler puts out per hour.
Just follow these simple steps:
- Place 6 identical containers in different areas of your lawn. Ensure that these are straight-sided.
- Run your lawn sprinkler for 20 minutes and turn it off.
- Measure the depth of water accumulated in each container.
- Add all depths and divide the sum by 6. This will give you the average water depth.
- Multiply the average depth by 3 to get your sprinkler’s hourly water output.
If this method sounds too complicated, you can put a flow timer on your sprinkler line. This handy device will monitor water flow and even help adjust it.
3. Calculate weekly watering needs
Time to measure how long to water lawn with sprinkler each week. For this, simply divide your lawn’s weekly watering needs by your sprinkler’s hourly output.
For instance, if your dwarf ryegrass lawn needs 1 inch of water per week, and your sprinkler’s hourly water output is 1½ inches, you will have to turn on your sprinklers for 2/3 hours (about 40 minutes) per week on average.
Image credit: @edengardeningtools
4. Decide how often to water your lawn
Satisfying your lawn’s weekly water needs in one day is not a good idea. You may end up with a swampy lawn perfect for fungi and pests, to say nothing of the impending root rot.
On the other hand, watering your lawn only a little every day is not ideal either. The water will not reach the grass roots, and the blades will start to turn brown.
To prevent either of the above cases, it’s best to set a lawn watering schedule. For this, understand the type of soil on your lawn.
Clay and loamy soils hold water longer but also absorb it slower. You can water these soils about 3 times a week. Sandy soil soaks up water quickly but doesn’t retain it for long. You can water this soil 2-4 times a week.
Now, to determine how long you need to run your sprinkler, divide the weekly watering time by the watering frequency. For example, if you need to water your lawn for 40 minutes two times a week, simply let your sprinklers run for 20 minutes each time.
Tip: For better water absorption, space your lawn watering sessions 2 days apart.
5. Keep an eye on the weather
Now that you have the basics down, it’s time to adjust your lawn watering schedule based on the weather. This will help save water and bring down your water bill, too.
During rainy weeks, you may have to water your lawn just once a week, if at all. To avoid overwatering, use a rain gauge to check how many inches of rain you’re getting. Subtract this amount from your lawn’s weekly watering needs.
Similarly, during sunny and windy weeks, you may have to water your lawn longer and more often. About half of the water is likely to evaporate from the soil.
6. Water early in the morning
Early morning, between 8 am to 10 am, is the best time to water the lawn. The sun is not strong and the wind is not as high around this time. That means less evaporation and a well-watered lawn.
Avoid running sprinklers during noon, as the water will evaporate, leaving your lawn thirsty. Likewise, watering your lawn at night is a bad practice. Your lawn will sit in water and may breed fungus and pests.
Watering established vs. newly seeded lawns
Your lawn’s water needs also depend on whether it is established or newly seeded:
- Established lawns: For an established lawn, 1 to 1½ inches of water each week is enough. This will keep the soil moist but not soggy. Feel free to water your lawn twice a week.
- Newly seeded lawns: Newly seeded lawns need water only in the top inch of the soil. To help your lawn establish roots, gently spray it once or twice a day. Once the grass grows to mowing height, you can treat it like an established lawn.
Watering cool vs. warm season grasses
To take better care of your lawn’s watering needs, keep in mind whether the grass is cool or warm season.
- Cool season grasses: Cool season grasses, like common bent, grow actively in autumn. They need about 1½ inches of water each week until the growing season ends and the first frost sets in.
- Warm season grasses: Warm season grasses, like Bermuda grass, do most of their growing in the summertime. They can do with less watering than cool-season grasses. Winter is a dormant season for these, so reduce watering.
Get a lush-looking lawn with the right amount of water. Image credit: @lawnlover_
Lawn watering FAQs
From telling when your lawn needs watering to how much water a sprinkler puts out, below are answers to the most frequently asked lawn watering questions:
How to tell if my lawn needs watering?
To know if your lawn needs watering, insert a screwdriver into the soil. If you can insert it easily, the soil is damp enough. If not, it’s time to run the sprinklers.
What does an overwatered lawn look like?
Overwatering your lawn promotes fungal growth. Mushrooms, brown patches and yellowing blades, accompanied by grey and slimy roots are some signs of an overwatered lawn.
How much water does a sprinkler put out?
Sprinkler water output varies, depending on its design and water pressure. Typically, most sprinklers put out 0.2 to 0.4 inches of water in 15 minutes.
Final thoughts
Get to know your lawn first, and you will be able to determine for how long the sprinkler lawn needs to be turned on.
Start by identifying the grass and how much water it needs each week. Then calculate your sprinkler’s water output. Once you have all the basics down, organise a weekly watering schedule and your lawn will thank you.
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