A free-standing field irrigation controller is selectively programmed by a personal computer over a radio link. The computer is equipped with software that displays a screen with seven horizontal time bands representing one day each, arranged vertically to display one week's time. Box icons representing watering settings for a plurality of zones can be dragged and dropped onto the time bands, copied and modified thereon as desired, to form a freely selectable watering schedule. Other selectable screens allow odd-days or even-days watering, sophisticated interval watering, global watering time adjustment, and a variety of manual functions. Selectable portions of the main screen can be enlarged as desired. Based on the selected schedule, the computer calculates and displays the monthly cost of water. Selected zones can be temporarily disabled to deal with weather or maintenance issues. A handheld global shut-off and manual watering remote and/or a separate radio-linked computer may be used in field maintenance.