A system (1) for modulating growth or attributes of at least one part (2) of one or more plants comprising chlorophyll is disclosed. The system (1) comprises at least one light emitting device (3), such as a light emitting diode (LED), for irradiating the at least one part (2), at least one light sensor (4) for picking up light from the at least one part (2), communication capabilities (5) for facilitating communication between the at least one light sensor (4), the at least one light emitting device, and a processor (6). The processor (6) reads data from the at least one light sensor (4) via the communication capabilities (5), generates a control signal based on the data and a reference, and then controls, based on the control signal, the at least one light emitting device (3) via the communication capabilities in order to modulate plant growth or plant attributes.