Justin White, Landscaping Lessons | Controller programming for irrigations systems – Santa Cruz Sentinel
Installing, navigating, and maintaining an irrigation controller can be a task in itself. I get dozens of calls every week about “how do I program my controller”, “my controller is not programmed properly” or “my sprinklers go on during the day”. Go through the steps below to better understand how your controller works and why it’s beneficial for your landscaping, wallet, and water conservation.
What is a controller?
A controller is the device or electronic “clock” that operates an irrigation system with the intended frequency, duration and start times. It plugs into a 120 volt outlet outside of your home or garage. Most systems typically have 12-14 gauge cables running from the controller to each of the valves. It sends a low voltage (between 12-14 volts) to operate a solenoid valve, which then operates and opens the electric valve. Water pressure is constantly built up in the valve. As soon as this signal is received, the solenoid valve 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 planned?
Determining how you should program your controller will depend on many factors including soil type, plant type, sun exposure, irrigation system, and outdoor humidity. Sandy soil usually needs a shorter duration but more frequent schedule. A clay floor is usually better with a start time. For example, a clay floor has to run for a total of 6 minutes, while the sandy floor program runs between 3 minutes, then waits for 20 minutes and then runs again for 3 minutes. This start-soak cycle lets the water soak 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 on your sprinkler valve and monitor it closely. Once water begins to form and drain off your lawn, you will know that by that time you have reached full capacity for it to hold. For example, let’s say that from minute 7, water spilled onto the sidewalk. So now you know you shouldn’t leave the irrigation valve running for more than 7 minutes at a time. Depending on how much water the sprinkler is putting out and how much water your lawn needs, you might find that 14 minutes per cycle, three days a week, is the amount required. Your plan should be to set the controller to start at 10 p.m. for 7 minutes and then again at 8 p.m. for 7 minutes. This achieves the total required run time of 14 minutes, but gives the floor a chance to soak up the previous water before applying the second. If you left the valve running for 14 minutes at a time, you would theoretically be wasting half of that water because it would sit together and drain.
What kind of system do I have?
Sprinklers: Sprinkler systems use an overhead application in which the water is distributed by spraying from a sprinkler head. Some sprinklers release water slowly like an MP rotator (at 3 gallons / minute) while others emit very quickly like the I20 sprinklers you would see on a baseball field (at 15 gallons / minute). It is important to know the difference in precipitation rates and flow in gallons / minute in order to properly set up your system, combined with knowing what type of sprinkler system you have.
Drip Systems: Drip systems use 1/2-inch flexible tubing 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 because they don’t waste as much water as sprinklers do. The challenge with these, however, is that it’s hard to see leaks and hard to know if they’re 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’ve installed the system correctly, you can calculate how much water each plant should receive and program your controller accordingly. Most drip systems run for 20-30 minutes per cycle, three times a week.
Baumsprudler system: Baumsprudler irrigation is similar to a cross between sprinklers and a drip system. While drip systems can dispense 1 gallon per hour, many arborists can dispense 1 gallon per minute. This is a 60x higher water release difference so knowing your system is very important. Most arborists are installed in pipes or directly on the surface, so it is often difficult to observe the system when it is on. Most bubbler systems should run for 5-7 minutes on a cycle of only 1-2 times a week. Trees rarely like deep watering, while a lawn more often prefers shallow watering.
Don’t be afraid to dig a little into your irrigation system and discover the ideal setup for your control system. It is so important to understand what type of application system you have and what type of delivery system you are using. At the end of the day, listen to your landscaping, it will give you clues about over- or underwatering. In general, the majority of the landscapes are overwatered. So before you add time to your controller, be sure to dig around your struggling plants to check for moisture levels. If it’s damp, you likely have too much water.
As we near Santa Cruz County’s Level 1 drought restrictions, reducing your landscaping water usage by up to 30% will add significantly to your overall savings!
Justin White is the CEO of K&D Landscaping, headquartered in Watsonville, California, and was named Business of the Year 2020 by the Pajaro Valley Chamber of Commerce. White is also the current president of the local California Landscape Contractors Association (CLCA) on the central coast. He is involved in several nonprofit organizations across the community. For more information on landscaping, outdoor and gardening needs, please contact K&D Landscaping at kndlandscaping.com.