Watering the lawn, how much, how often and when

A lawn typically needs about an inch of water a week, counting the rain. Your climate, the recent weather and what's planted all change that amount. Watering too often can drown plants or leave the grass with shallow roots. The tuna-can test below tells you how long your own sprinkler takes to put down the water.

What you need

• A few empty tuna cans, or other short straight-sided cans
• A ruler
• A timer, or the clock on your phone

Steps

1. 1

   Ask your water utility first

   It can tell you how much to water and when.

   5 min

2. 2

   Set out the cans

   Place a few empty tuna cans around the lawn, in the sprinkler's path.

   5 min

3. 3

   Time the half inch

   Turn the sprinkler on and time how long it takes to fill the cans to half an inch. Check with the ruler.

   30 min

4. 4

   Water that long, twice a week

   Watch how the lawn responds, and adjust for the weather.

   1 min

5. 5

   Skip the middle of the day

   In the middle of the day, the hot sun evaporates much of the water before the grass gets it.

   1 min

6. 6

   Stop when it pools

   Turn the sprinkler off as soon as water starts to pool. On clay soil or a slope, run the sprinkler in short bursts with breaks between, called cycle-and-soak, so the water has time to sink in.

   1 min

7. 7

   Check where it lands

   Watch one full run. Turn any sprinkler that sprays the driveway, sidewalk or house back toward the lawn.

   5 min

With an in-ground system

Homes with clock-timer irrigation systems use about 50 percent more water outdoors than homes without them. Check the system once a month while it runs:

• Heads that tilt or don't pop up fully. They spray the wrong spot.
• Broken heads. Put a flag beside each one so you can find it for the repair.
• Pooling between runs. It can be a sign of an underground leak.
• Gaps in coverage. The spray from each head should reach the next one, called head-to-head coverage.

A certified irrigation professional can run the same check. Change the schedule with the seasons. A WaterSense labeled controller does this on its own, using the local weather or the moisture in the soil. Fall lawn care covers the lawn once the watering season ends.