An apparatus comprising an irrigation sprinkler body cover with an integrated battery-powered decoder is disclosed. A method of retrofitting existing irrigation systems to wirelessly communicate with one or more of the present apparatus is also disclosed. Concerning the present method, an irrigation controller provides message data to a gateway regarding the control of irrigation valves. The gateway contains configurable encoder software that encodes and then wirelessly transmits the message data, for example via long-range radio hardware at 902-928 MHz frequency. The encoded data is received by a present apparatus to which the message is addressed. The apparatus decodes the message data and subsequently provides a power signal via wire to one or more proximally-located DC latching solenoid valves to control the irrigation valves according to the user input.
