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Oscillating sprinklers can be a homeowner’s best friend, but they don’t always come with instructions. The big question is always: How long should a lawn be watered with an oscillating sprinkler?
The good news is that there are some clear best practices for watering a lawn with a sprinkler. In general, 15 minutes in each zone of a yard should be sufficient for watering the grass and keeping it healthy.
Of course, that timeframe assumes ideal conditions in terms of weather, climate, grass type and output from the sprinkler. All of these factors add up and affect how long and how often a lawn should actually be watered with a sprinkler. Keep reading for more information to help you understand how long you need to water your lawn.
What to Consider what Determining How Long to Water
One of the trickier elements of measuring how long to use a sprinkler is that a lawn generally needs about an inch of water per week between rainfall and regular watering.
Climate and Weather
This is a good time to start thinking about climate and weather. More arid areas don’t get regular rainfall, so lawns need frequent, long sprinkling sessions in order to stay moist and healthy. Meanwhile, lawns in humid and temperate zones might receive steady rainfall so less sprinkling is needed. Think about the climate and weather to gauge how much a sprinkler should be turned on in order to avoid overwatering.
Determining Your Sprinkler's Waterflow
Another factor to keep in mind is the sprinkler’s level of water flow. Put simply, different sprinklers have different speeds and put out varying amounts of water. The “can” method is largely considered the best way to figure out the rate of a sprinkler.
How to Determine Waterflow
To get started, clean out some used cans. Any type of can will do here as long as it’s a couple of inches deep. It can be a tuna can, soup can, coffee can, whatever is available. Place the cans around the lawn in the general radius of the sprinkler and turn the water on for 15 minutes.
Next, turn the water off and use a ruler or measuring tape to see how deep the water is in each can. Add that total up and divide it by the number of cans to figure out the average. Then multiply the average by four to find out what the rate of water flow is for an hour.
Here’s an example to make it clearer: Five cans were placed around a sprinkler and the water ran for 15 minutes. Can #1 had 1.5 inches of water. Can #2 had 1 inch of water. Can #3 had 1.5 inches of water. Can #4 had 0.5 inches of water. Can #5 had 0.5 inches of water. Added together (1.5+1+1.5+0.5+0.5), that equaled 5 inches of water. Divide that by five because there were five cans (5 inches/5 cans) so that’s 1 inch on average. Multiplied by 4 is 4 inches in an hour.
In that example, 15 minutes with an oscillating sprinkler is sufficient for watering a lawn because the average water flow is 1 inch every 15 minutes. Letting the sprinkler run longer than that would lead to overwatering.
So if this sprinkler was on a lawn in a moderate climate without much rain, 15 minutes is all it would take for watering. If it rained half an inch one week, then the sprinkler would only need to run for 7 minutes and 30 seconds.
How Often Does a Lawn Need to be Watered With a Sprinkler?
So now that it’s understood how long it takes to water a lawn with a sprinkler, it’s time to think about frequency. For this, it pays to go back to two specific factors: climate and weather.
As discussed earlier, a healthy lawn receives an inch of water per week. This includes rainfall, so make sure to pay attention to local meteorologists and see how much rain falls with each storm. These insights could be the difference between overwatering the grass and getting everything just right.
There may be local resources to help figure out the ideal frequency. The city of Seattle offers a guide to residents and Agriculture and Natural Resources at the University of California that provides a table on measurements for lawns in the San Joaquin Valley, an arid area.
These are instructive because these places are in different climates. Seattle famously is a rainy city; therefore, residents don’t need to use their sprinklers that often. The San Joaquin Valley gets little rain, so sprinklers need to run often to help lawns grow.
Look to see if there are local guides and resources. But always remember to keep rainfall in mind when deciding how often to turn the sprinkler on for watering the lawn.
How Long Should Sprinklers Run in Each Zone?
Zone sprinkling ensures that a lawn is watered evenly, which is especially helpful on larger tracts of land. And while it may seem difficult to figure out how long to run sprinklers in every zone, the answer is pretty easy.
It all comes down to that same inch of water per week. That is the standard to shoot for everywhere on a lawn. With a zone system, perform the “can” method throughout different zones to determine how often and how long each sprinkler needs to run.
How Much Water Does a Sprinkler Use in 1 Hour?
The amount of water a sprinkler uses depends on the type of hose used with it. The Washington Suburban Sanitary Commission in Maryland estimates that a sprinkler using the 1,020 gallons of water in an hour. Even though lawns only need an inch of water per week, this is why lawn care is the biggest uses of household water.
With all this in mind, using a sprinkler to keep a lawn nice and healthy should be easy. Just remember that an inch of water per week is all a lawn needs, so feel free to turn it off if there’s been lots of rain.
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