Various implementations disclosed herein includes a method for operating lighting fixtures in horticultural applications. The method may include receiving a user input of a desired irradiance for a first color channel of one or more lighting fixtures that irradiates a plant bed, in which each of the one or more lighting fixtures comprises at least one light emitting diode (LED) array, determining, for each of the one or more lighting fixtures, a PWM setting of the first color channel such that each of the one or more lighting fixtures irradiate the plant bed at the desired irradiance based on calibration data stored in each of the one or more lighting fixtures, and applying, to each of the one or more lighting fixtures, the determined PWM setting of the first color channel.