Smart controllers might not be as reliable as expected, according to a recent study from Texas A&M University. Researchers have found that smart controllers get confused and can overcompensate in erratic weather.

The experiment has tested eight controllers over the past three years. In the past year, three of the eight controllers were shown to over-irrigate, while the remaining five did not apply enough water. In 2010, it was too much rain that threw off the controllers. Only those equipped with tipping-bucket rain gauges were accurate.

To ensure that the controllers act as designed, they allowed each manufacturer to come in and program them appropriately. Controllers have improved in the last three years over which the experiment has been in progress, but they still perform inconsistently.

Smart controllers rely on weather data to calculate and apply the correct amount of water needed by plants, without relying on human intervention. They combine weather data with a variety of sensors to measure rainfall, heat, and sunlight.

The full results are included in the recent report on smart controller testing and performance found on the Irrigation Technology Center website at