The Pro-Leaf PPM-B1, digital CO² controller, provides simple and precise control of a 240 Volt CO² generating device with modes for both increasing and decreasing CO². Also featuring fuzzy logic operation which offers additional accuracy when utilizing CO² supplementation. Adjustable set points range from 400-2000 parts per million with an accuracy of +/-100 PPM and an adjustable deadband. A remote sensor with 4.5 m cable, accurately monitors the garden’s PPM levels and relays this information to the controller for display in real-time. An integrated photocell allows for day, night, or continuous operation and the unit records maximum and minimum values for later viewing.