Time to Irrigate
I have my sprinkler clock set to run 10 minutes in each zone every day. My neighbor tells me this is too often to irrigate. What is your recommendation?
With the exception of newly planted plants, I did not have to irrigate until recently. Even now there is still moisture in the soil available for deep rooted plants. When hot weather finally comes, sometimes we panic and turn the sprinklers on every day. Again, with the exception of newly transplanted plants, daily watering is not necessary and is even detrimental in some situations. Brief daily watering keeps the top of the soil moist, which encourages weed seed germination. It also encourages moss growth on top of the soil in shady areas. In most cases twice a week irrigation is adequate until hot weather comes. Then a 2 to 3 day interval may be necessary.
The best way to irrigate is to apply enough water to wet the entire root system of shallow rooted plants like grass. Then allow enough time for the soil to dry on top. Depending upon your sprinkler system, it usually requires a minimum of 20 minutes to apply enough water to wet the soil several inches deep. Rotating sprinkler heads may require an hour or longer.
If your soil will not accept that much water at one time without runoff, run sprinklers through the cycle twice at half the amount of time.
You can determine how long it takes to deliver 1/3 to 1/2 inch of water using your sprinklers by placing shallow cans such as tuna fish cans on the lawn. Water for a specific interval such as 30 minutes and then measure the accumulated water with a ruler.
Run sprinklers through their cycle on a two minute cycle so you can check them at least once a month. This will allow you to catch plugged or mis-aligned sprinkler heads before dry spots develop.
Allen Wilson
Allen has been writing about gardening for over 30 years. He is a retired professor of Horticulture.