Installing, navigating and maintaining an irrigation controller can be a job all in itself. I receive dozens of phone calls every week on “how to program my controller”, “my controller isn’t programmed right” or “my sprinklers are coming on during the day”, etc. Flow through the following to better understand how your controller works and why its beneficial for your landscaping, your wallet and water conservation.
What is a controller?
A controller is the device, or electronical “clock”, that operates an irrigation system with intended frequency, duration and start times. It plugs into a 120 volt outlet on the outside of your home or in your garage. Most systems typically have 12-14-gauge wires that run from the controller to each one of the valves. It sends a low amount of voltage, (between 12-14 volts), to operate a solenoid which then actuates and opens the electric valve. Water pressure is built up in the valve at all times, so once that signal is received, the solenoid opens and pressurizes the sprinkler or drip system. Once the electronic current stops, the solenoid closes which in turn closes your irrigation valve and stops the flow.
How should it be scheduled?
Determining how you should program your controller depends on may factors, including soil type, plant type, sun exposure, irrigation delivery system and exterior humidity. Sandy soil typically needs a schedule with shorter amounts of duration, but with more frequency. A clay soil usually does better with one start time. For example, a clay ground may need to run for 6 minutes total, while the sandy soil program switches between running for 3 minutes, then waiting 20 minutes, then running for 3 minutes again. This start-soak cycle lets the water penetrate into the ground without causing flooding and can be set up by adding multiple start times on your controller.
The best way to know how long to water your soil before it floods is to turn your sprinkler valve on and monitor it closely. Once water starts to puddle up and flow off your lawn, you’ll know you have reached full capacity of what it can take in that period of time. For example, say at minute 7, water started running onto the sidewalk, so now you know you shouldn’t run that irrigation valve for more than 7 minutes at a time. Depending on how much water that sprinkler puts out, and how much water your lawn needs, you may find that 14 minutes per cycle, 3 days a week is the necessary amount. Your plan should be to set the controller to start at 10:00 pm for 7 minutes and then again at 2:00 am for 7 mins. This will accomplish the total 14 minute requirement run time but gives the soil the chance to soak up the previous water before applying the second. If you were to run the valve for 14 minutes straight, theoretically you’d be wasting half of that water because it would puddle up and run off.
What type of system do I have?
Sprinklers: Sprinkler systems use an overhead type of application where the water is dispersed by spaying out of a sprinkler head. Some sprinklers put out water slowly like a MP rotator (at 3 gallons/minute), while some put out really quickly like I20 sprinklers you would see on baseball field, (at 15 gallons/minute). Its critical in knowing the difference of precipitation rates and gallon/minute flow in order to adjust your system properly, in combination of knowing what type of sprinkler system you have.
Drip Systems: Drip systems utilize ½” flexible piping with small emitters to apply water directly to the plant root system. These types of systems tend to be the most common in recent years as they do not waste as much water as sprinklers. The challenge with these though, is that it is hard to see leaks and difficult to know if they are on or off. Drip emitters can range from 1 gallon per hour to 5 gallons per hour so it’s important to put the right emitters on the right plants. Once you have the system installed correctly you can then calculate how much water each plant should receive and program your controller accordingly. Most drip systems will run 20-30 minutes per cycle at 3 times per week.
Tree Bubbler System: Tree bubbler irrigation is similar to a cross between sprinklers and a drip system. While drip systems can give out 1 gallon per hour, many tree bubblers can give out 1 gallon per minute. This is a 60x higher amount of water release difference, so it’s very important to know your system. Most tree bubblers are installed in tubes or right at the surface, so its often hard to observe the system when it’s on. Most bubbler systems should run for 5-7 minutes and on a cycle of only 1-2 times per week. Trees like deep watering on an infrequent basis, whereas a lawn prefers shallow watering more often.
Don’t be afraid to do a little “digging” into your irrigation system and discover the ideal set up for your controller. It’s so important to understand what kind of application system you have and what type of delivery system you’re running. At the end of the day listen to your landscaping, it will give you indications of over- or under-watering. In general, the majority of landscapes are overwatered, so before you add time to your controller make sure to dig around your struggling plants to check the moisture content. If it’s damp, you are probably overwatering.
As we head into the Stage 1 Drought Restrictions for Santa Cruz County, reducing your landscaping water use by up to 30% will greatly contribute to your overall savings!