Automatic sprinkler systems can make irrigating our landscapes (especially lawns) much easier, and they can also help us water more intelligently. In our area, we are usually encouraged to water lawns early in the morning or late at night. This is simple with a sprinkler system timer that can be set for any time of the day or night. Consistent watering is also important, especially during drought (a.k.a. now), and the timer easily takes of care of making sure your lawn is watered when you are away on vacation. In a previous post, I described rain sensors that can be added to your system so that it won’t run during or immediately after a storm. You can even find sprinkler controllers that incorporate weather sensors that turn the system off during high winds and incorporate local ET data to set sprinkler zone times.
But here is another simple thing you can do with nearly all of the most basic sprinkler system timers that will more efficiently irrigate your lawn – make use of the multiple start times to run your stations in multiple, shorter spurts. See the three “Start Time” buttons at the bottom of the timer in the photo above? You can use those to do this. For example, zone 1 of my overhead sprinkler system currently runs for seven minutes, three times, an hour apart (for a total of 21 minutes over three hours). Another zone that waters a buffalograss area runs four minutes, three times, an hour apart.
Why?
If you’ve already done the calculations to figure out how long your sprinkler should be running each month to efficiently water your turf, kudos to you! (If not, you can do so using the Lawn Irrigation Calculator from Colorado Springs Utilities – see link at the end of the article.) I figured out I needed to apply 42 minutes per week on zone 1 at this point in the growing season. Usually I would do that over three days, but during watering restrictions, I’m limited to two days per week. So I know I need to apply 21 minutes of water each watering day. Since I have slow-draining clay soil, if I run a sprinkler station for 21 minutes, it starts to run off on to the driveway or sidewalk because water is being applied quicker than the soil can absorb it. So it works much better to break that 21 minutes up into three 7-minute runs. Now all of the water makes it into the soil. What if you have sandy soil? Fortunately, the same technique works but for a different reason. Sandy soil drains much more quickly than clay or loam. So if a homeowner with sandy soil applies 21 minutes worth of water in one shot, much of that water ends up draining down below the root zone of their turf (6-to-8-inches). Breaking the run into three 7-minute sessions gives the lawn a much better chance of using all of that water. In fact, if I had sandy soil, I might try to break up the three sessions by more than an hour – perhaps even doing two of the sessions in the morning and one more in the evening.
How?
As I mentioned, the “Start Time” buttons on my timer are what I use to make this possible. Most timers will have similar buttons, and many may have more than three! So for each station, you’ll need to program in three different start times. Take into account how long it takes all of your stations to run when choosing your start times. You want to be sure they all have a chance to finish running before station 1 is cued to start again. For example, this month, it takes 20 minutes for all four of my stations to complete one run. Station 1 starts at 6:00 a.m and runs 7 minutes, Station 2 starts at 6:07 and runs 5 minutes, Station 3 starts at 6:12 and runs 4 min, and Station 4 starts at 6:16 and runs 4 min. All of the stations have had a chance to finish before station 1 is called up to run again at 7:00 a.m. If I told Station 1 to start again at 6:15 a.m. (while one of the other stations was still running) the sprinkler timer would just ignore that start time since it cannot run two stations at once).
Other Helpful Irrigation Tips
Tools You Can Use: Meet the Rain Sensor
Growing Season Precipitation for Colorado Springs the Past Twenty Years
Water Saving Tips from Colorado Springs Utilities
Lawn Irrigation Calculator from Colorado Springs Utilities (NOTE – This link downloads an Excel spreadsheet file!)
Contributed by Carey Harrington, Certified Colorado Gardener and Colorado Native Plant Master
Pikes Peak Area Garden Help 
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