The present invention provides an irrigation control system in which a device
(irrigation scheduler) automatically modifies irrigation schedules of installed
irrigation controllers to affect irrigating of the landscape based on the water
requirements of the landscape plants and comprises: providing an irrigation controller
programmed to execute irrigations on watering days by closing an electrical circuit
connecting the controller and at least one irrigation valve; providing an irrigation
scheduler programmed to execute irrigations on substantially equivalent watering
days as the irrigation controller; and the irrigation scheduler selectively interrupting
the electrical circuit to control the execution of irrigations on watering days.
Preferably the microprocessor uses either an ETo value or weather data used in
calculating the ETo value to at least partially derive the improved irrigation schedule.
