The irrigation controller acts as the central nervous system for a landscape watering system, automating the process by opening and closing individual zone valves according to a preset schedule. The underlying programming logic remains consistently structured across all controllers. Efficient watering is achieved by correctly balancing three core elements: the time the system starts, the duration each zone runs, and the frequency of the watering cycle. Correct programming ensures that water is delivered precisely when the landscape needs it, minimizing waste and promoting healthier plant growth.
Preparing the Controller for Programming
The first step in setting up any controller is to ensure it has the correct reference point for time and scheduling. Locate the setting position, often labeled “Set Clock” or “Date/Time,” and use the dedicated buttons to input the current day, month, year, and the accurate time of day, paying close attention to the AM/PM designation. This date and time function is typically battery-backed, meaning the information will be retained even if the main power is temporarily lost.
Most modern controllers offer multiple independent programs, often designated as A, B, and C, which are designed for different areas of the landscape. These programs allow for varied watering requirements; for instance, Program A could be set for a lawn area needing frequent watering, while Program B is reserved for shrub beds that require less water on different days. Before beginning the detailed setup, you must select the program you intend to edit, usually by moving a dial or pressing a specific “Program” button until the correct letter appears in the display. Finally, it is best practice to turn the main dial to the “System Off” or “Set Clock” position to prevent any accidental watering cycles while you are programming the schedule.
Setting the Core Watering Schedule
The core schedule requires inputting the start time, the run time for each zone, and the watering days. The start time tells the controller exactly when to begin its watering sequence, and this time refers only to the moment the first zone in the program begins its cycle. Subsequent zones will start immediately after the previous one finishes running, continuing sequentially until all zones assigned to that program have completed their set duration.
Many controllers allow for multiple start times per program, which is a useful feature for deep, infrequent watering or for managing water runoff. If the soil has a low infiltration rate, splitting a long watering duration into two or three cycles spaced an hour apart allows the water to soak in, preventing waste from surface runoff. The run time, or duration, must be set individually for each zone, directly corresponding to the plant material and soil type in that area. For example, a zone with spray heads on sandy soil might need three to five minutes, while a zone with rotor heads on clay soil may require a longer duration, possibly 20 to 40 minutes, to apply the necessary amount of water.
The final element is setting the watering frequency, which dictates the days the program will be active. Controllers offer flexibility here, typically allowing selection of specific days of the week (e.g., Monday, Wednesday, Friday), odd or even calendar days, or interval watering (e.g., every three days). Selecting the correct frequency is determined by the local climate, water restrictions, and the specific water needs of the plants in that zone. Once the start time, run times, and watering days are set, the controller can be switched to the “Auto” or “Run” position to allow the automated schedule to begin.
Adjusting the Program for Changing Conditions
Once the core schedule is established, advanced features allow for seasonal adjustments without the need to reprogram every zone’s run time. The Seasonal Adjust or Water Budgeting feature globally modifies the duration of all run times in a selected program by a single percentage. This is particularly efficient for managing the system during weather transitions, such as reducing the run times to 50% in cooler fall months or increasing them to 120% during peak summer heat. By adjusting this percentage, the system automatically calculates the new duration for every zone, saving time and ensuring water application closely matches plant demand.
The Rain Delay or System Suspension function is used to temporarily pause the entire schedule for a specific number of days, most commonly set for 24, 48, or 72 hours. This is highly useful after significant rainfall, allowing the soil to dry out and preventing overwatering without erasing the complex programmed schedule. The controller will automatically resume the programmed cycles once the set delay period has elapsed.
For maintenance or troubleshooting, the Manual Operation feature allows for a quick, unscheduled run of the system. This can be used to activate a single zone for a set number of minutes to check for leaks, or to manually initiate a full-program cycle for a one-time supplemental watering. Using this feature does not affect the stored core program, ensuring the regular schedule remains intact for the next planned watering day.