What is an irrigation timer? How do I program it?

What is an irrigation timer? How do I program it?

Want to save water and still have a nice lawn?    Try some of these tips to conserve water.

First let’s look at the timer or irrigation controller. You likely see multiple stations. A typical residential landscape will have between 5 to 9 stations but larger homes with large yards will have many stations. While the stations might be similar, they are not identical nor should they all have identical irrigation run times.

"Photo courtesy of Hunter Industries Incorporated."
"Photo courtesy of Hunter Industries Incorporated." 

Here is why.

Consider, sun versus shade, east versus west exposures as well as plant types among other things.  These will influence the amount of water and thus run time for each station.  There are more complicated concerns such as pipe sizes, water flow, soil types and slope and more.  There is a difference between design efficiency and programming efficiency.  This article is more focused on what the homeowner can do to improve the program or run time efficiency on their own as general advice to help save water. 

Simply follow these instructions and you will likely save water and have a better-looking landscape without a service call or water audit.

1.            Run the system with your existing or proposed run time.

2.            Do you see obvious leaks or flooding? 

3.            Are all areas getting some water?

4.            Note any run off and how long the system operates before run off occurs.  

5.            After operating the system walk the property to observe dry or soggy areas.

Note, dry soil will often take more water than will soil that has some level of moisture already. This is particularly true in the heavy clay soils we find in Grand Prairie and much of North Texas  It is best to perform this test on relatively moist soil.   Different soil types will infiltrate water at different rates depending on the existing level of moisture already present. Sand will let irrigation water infiltrate faster than Loam, Loam faster than Clay.  

There is a general concept often promoted of watering deeply and infrequently to develop deep roots and drought resistance.   This is generally true and we advocate following this advice even if there are no watering restrictions in your area at this time.  It is best to condition the lawn before restrictions are enforced.  Deeper rooted systems are more drought resistant.  

Watering deeply means to just beyond the root depths by about 1 inch and not any more than that because the plants can not use it.  The actual watering frequency is determined by root depth and a big word Evapotranspiration (ET) and plant type.  ET is a combination evaporation of water from the soil, and the plants use of water.  Let’s simply say most established turf grass can survive in North Texas 3 or 4 days even in the hottest summers.  If for example, your root depth is 6 inches, you should water when the top 3 Inches of water are lost to ET.  

Most irrigation sprinklers will put out more water than the soil can absorb in a short period. This is particularly true of clayey type soils. One feature of the controller is the multiple program start times.

Running the system for Two 5 Minute Cycles on the same day is often better than running for 10 minutes.   This is most true on heavy clays and on slopes.   For example, run all the stations for 5 minutes at 3 AM, if you have 5 stations this will take about 25 minutes to complete.   Set up a second start time at 4 AM.  If you need more water because you see dry areas, perhaps add a 3rd start time at 5 AM.  


Brands and Types of Sprinkler spray heads put out different amounts of water.  The goal is to get about 1/2 of water on the lawn twice per week.  Knowing the design output will let you estimate the run time.  Mixing different brands or types of sprinkler nozzles will mess up the whole design.   You can place catch cans out to measure the amount of irrigation water applied to the lawn, some people use empty tuna cans for this purpose.  Hancock Glen uses a professional system with specially calibrated catch cans and software to calculate the proper run time.   

  • Full Sun areas require more water than shady areas. 
  • Slopes will result in runoff so multiple start times on shorter cycles are needed. 
  • Clay soils also benefit from multiple start times. 
     

Walk the property after a few days, look for lush green versus dry areas, shorten the run time on the lush areas a minute or two and increase the dry areas a minute or two.   Repeat this several times and you will have calibrated the run time to match your expectations of the lawn conditions you desire.  Frankly, some people want a healthy lawn and others want a lush lawn.  Nonetheless, if the lawn is lush, perhaps you can trim back the water use by 10 to 20% and get the same results.  

Most lawns will need the most water in the peak of summer heat, perhaps 30 to 40% more water.  Summer is the best time to check the system as described above.  Once you get the program dialed in, each station adjusted for the environmental condition like full sun on the west versus the north side of the home, you can then use the seasonal adjust function.   If summer is 100% then Spring and Fall are  50% to 65% and the global or seasonal adjust function will reduce all the lawn sprinkler stations by that amount.    

Plants need water in the winter as well but maybe only 10 to 20%.  A good rule of thumb is to only use the lawn sprinkler in the winter using the manual feature if there has not rained in 3 weeks.  Last but not least, have a rain/freeze sensor so the irrigation system does not operate during those times. 

Please call us if you would like a system inspection or an Irrigation Audit.