Liquid additive controller system and method for horticultural watering systems

A liquid additive controller system for a horticultural watering system, the liquid additive controller system comprising:

• a controller unit installed in proximity with a sprinkler timer, said sprinkler timer configured to control the horticultural watering system, wherein said controller unit is connected to said sprinkler timer and whereby said sprinkler timer provides zone output signals to said controller unit;
• the horticultural watering system is divided into a plurality of zones, each of said plurality of zones comprising at least one sprinkler valve;
• said controller unit controls at least two liquid additive containers connected to said horticultural watering system and controlled by said controller unit, whereby one or more of said at least two liquid additive containers can be directed to one or more injectors;
• at least one remote unit installed remote from said controller unit in proximity with one said valve, said at least one remote unit in communication with said controller unit;
• said at least one of said one or more injectors controlled via said remote unit;
• wherein said plurality of zones comprises at least three zone valves;
• and
• wherein three of the wires that control the plurality of zones are repurposed to send power and communication signals to the remote unit to signal one or more of the liquid additive injectors to inject at a user programmed rate, as well as to control at least one of the three zone valves that were originally controlled using the wires that were repurposed for said power and communication, thereby freeing up extra wires for use on additional zones.