When to Turn On Your Sprinklers in Westchester and Greenwich

Why Timing Matters Here

Westchester County and Greenwich sit in a climate where the ground freezes in winter. Water left in pipes or valves can freeze, expand, and crack fittings or burst lines. Once the soil thaws and the risk of a hard freeze is behind us, starting the system is safe. Start too soon and one cold night can mean costly repairs. Wait too long and the lawn dries out right when it is trying to green up.

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The Right Window for Our Area

For properties in Hartsdale, Bronxville, Larchmont, and the rest of Westchester and Greenwich, the usual safe window to turn on sprinklers is from mid April through early May. Soil temperatures need to stay above freezing and daytime weather should be consistently mild.

Use the calendar and the weather, not a fixed date

• Watch for a stretch of nights that stay above freezing (about 32 degrees or higher).
• Aim for after the last typical frost, which in our area is often around late April or early May.
• If you have had your system winterized, schedule irrigation startup with a pro so they can check for leaks and adjust heads before you rely on it.

What to Do Before You Turn the Water On

Do not simply open the main valve and run every zone. A few steps first will protect your system and your wallet.

Inspect above ground first

• Walk the property and look for broken or tilted heads, cracked valves, or exposed pipes that might have been hit by plows or frost.
• Clear leaves, mulch, and debris away from heads so they can pop up and spray freely.

Turn on the system slowly

• Open the main water supply slowly so pressure builds gradually and you reduce the chance of blowing a fitting.
• Run each zone for a short time and look for puddles, geysers, or weak spray that could mean a leak or clog.

Set the controller for spring, not summer

Lawns need less water in spring than in July. Start with shorter run times and fewer days per week. You can increase both as the weather heats up and the grass is actively growing. Overwatering in April and May encourages shallow roots and fungus.

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When a Pro Should Do the Startup

Many homeowners in Mamaroneck, Pelham, and Greenwich prefer to have irrigation professionals handle the startup. A full service visit usually includes checking backflow devices, testing each zone, adjusting spray patterns, and setting the controller. That way you know the system is ready and you are not wasting water or missing a broken head.

If you had winterization done in the fall, the same team often does the spring startup and can fix small issues before they become big ones.

Common Mistakes to Avoid

• Turning on too early. One late freeze can damage pipes and valves. Waiting until the freeze risk is over is cheaper than replacing lines.
• Running zones too long at first. Short run times let you spot problems without soaking the yard.
• Skipping a walkthrough. Catching a broken head or leak early saves water and avoids dead spots in the lawn.

Bottom Line

For Westchester and Greenwich, plan to turn on your sprinklers in the mid April to early May window, after the ground has thawed and nighttime freezes are unlikely. Inspect the system, open the main slowly, run each zone briefly, and set the controller for light spring watering. If you want it done right and checked for damage, schedule a professional irrigation startup so your lawn in Scarsdale, White Plains, or Greenwich gets the water it needs without the risk.