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In spring, let Mother Nature water the lawn

Yes, your grass is turning green. No, you shouldn’t turn on your irrigation system. Here’s why.

Welcome to the roller coaster of spring weather in the Mile High City.

At any given time, it can snow, hail, rain or be unseasonably hot. But just because the spring season has officially sprung doesn’t mean it’s time to kick on your irrigation system.

Spring in Colorado often means warm, sunny days, rain or snow, and sometimes blizzard conditions. Photo credit: Denver Water.


That grass in your yard has a secret buried deep in its soil: winter moisture.

With short daylight hours, cool nights and the sun traveling lower across the sky, the water in the soil evaporates more slowly than it does in the summer. So while your grass lies dormant, it still has moisture sustaining its root system.

It may be tempting to start up the irrigation system when the grass begins to turn green, but our experts advise holding off just a bit longer because the potential for winter weather lingers.

That's because we can have deep freezes in April and deep freezes will damage an irrigation system that was not properly winterized last fall, or turned on too soon this spring.

Waiting until after the last freeze — typically around May 5 — to turn on your system.

While leaks or breaks can occur on exposed pipes and backflow devices above ground, damage can occur underground, as well. When temperatures drop below 30 degrees, water sitting in the pipes can freeze and expand, cracking the pipe. This damage may not be discovered until abnormally high water bills show potential leaks in the system.

Irrigation system leaks can lose as many as 10,000 gallons per month per zone. Aside from the higher bills and wasted water, repair costs can also put a dent in your household budget.

You can avoid this by simply rolling out the garden hose and hand-water trees, perennials and late-fall plantings during warm, dry periods. If your lawn has brown spots, use water efficiently by hydrating the distressed areas instead of the entire lawn. Just don’t forget to disconnect the hose from the spigot in case freezing weather moves in.

If you are concerned about your soil’s moisture, check it by inserting a screwdriver into the ground; if it goes in easily, it’s got enough water. You can also aerate your lawn to help water absorb rain or snowmelt to provide added moisture without watering.

And what should you do if you turned on your irrigation system in March? Winterize and shut off your system until after the last freeze to protect it from potential damage.

gif explaining why you should not turn on your irrigation system in the early spring