Setting a fixed watering schedule often leads to wasted water and unhealthy plants, as a summer schedule inevitably overwaters the landscape in cooler months. Seasonal Adjustment, sometimes called Water Budgeting, is the primary solution. It modifies the entire watering program to match the landscape’s fluctuating needs throughout the year, optimizing water efficiency without reprogramming every zone individually.
Understanding the Concept of Seasonal Adjustment
Seasonal Adjustment is a system-wide multiplier that automatically scales the duration of all programmed watering cycles. This feature is tied to evapotranspiration (ET), the combined measure of water lost from the soil through evaporation and from plants through transpiration. As temperatures rise, wind increases, and humidity drops, the ET rate increases, meaning the landscape needs more water. Conversely, cooler periods decrease the ET rate, reducing the plant’s water demand. The adjustment ensures the water applied precisely matches the water lost, preventing shallow root growth, disease from overwatering, or drought stress during peak heat.
How the Controller Implements the Change
The practical mechanics of Seasonal Adjustment involve applying a single percentage factor to the entire irrigation schedule. A user sets a base program, which represents the maximum watering time needed during the peak heat of summer, typically set at 100%. If a zone’s base run time is 10 minutes, and the Seasonal Adjustment is set to 50%, the controller implements a new run time of 5 minutes. This percentage is applied universally to all zones and program start times. This feature eliminates the need to manually alter the run time for every valve as the seasons change. The adjustment range commonly extends from 0% (off) to 150% or more.
Distinguishing Manual and Smart Systems
The method of determining the Seasonal Adjustment percentage is the main difference between controller types. Traditional or manual controllers require the user to check local weather data, often referencing historical averages, and then physically input the percentage. This adjustment is static, requiring the user to manually change the value whenever the weather shifts significantly. In contrast, modern smart controllers manage Seasonal Adjustment automatically. These systems connect to Wi-Fi to pull real-time, local weather data, including temperature and wind speed, to calculate the precise daily ET rate. The smart controller then automatically adjusts the watering duration percentage, sometimes daily, ensuring optimal water application without user intervention.
Steps for Effective Seasonal Programming
To use Seasonal Adjustment effectively, the first step is to establish an accurate base schedule, which is the 100% setting. This 100% time should be the run time required to meet your landscape’s needs during the hottest, driest time of the year, often July or August. Once the base time is set, individual zone run times should not need to be changed again. For users with manual systems, the adjustment must be proactively managed during seasonal transitions. A good practice is to reduce the percentage to around 70% in the spring and fall and drop it to 20% or less in the mildest winter months. Manual adjustments should be made monthly, or at minimum, at the start of each major season.