A seed monitor for a multiple station planter includes a light source adjacent each seed path and a pair of phototransistors positioned in alignment with each light source. The phototransistors for each seed path are connected to pulse generating means, each of which provide a constant width pulse in response to an interruption in light received by a phototransistor from its light source. An OR gate is connected to the pulse generating means so as to provide an output signal whenever there is a pulse at one of its inputs. The light sources for the multiple seed paths may be operated to periodically monitor each planting station.