An indoor gardening appliance includes a grow module that is seated on a turntable that is rotatably mounted within a grow chamber and is rotated by a drive assembly. A position sensing assembly monitors an angular position using two proximity sensors, such as Hall-effect sensors, mounted below the sump at the same circumferential position but at different radial positions. The turntable includes a plurality of proximity indicators, such as magnets, positioned at each of three circumferential positions on the turntable and at different radiuses to define a two-digit binary code corresponding to each of the three circumferential positions that is detectable by the proximity sensors.