Abstract: There is provided a modular LED system comprising a frame (1) having a plurality of light emitting diodes (LEDs) (8) of at least two different colors for generating light within a color spectrum, said LEDs (8) being mounted, preferably clickable, on or adjacent to a, preferably heat conductive, plate equipped with cooling means (3) for cooling the LEDs with cooling medium; a processor for controlling an amount of electrical current supplied to the plurality of LEDs, so that a particular amount of current supplied thereto determines a color of light generated by the plurality of LEDs, —and a flat translucent member (5) having translucent lenses (4) associated with the LEDs for decreasing or increasing the diffusion angle for light emitted from each LED. The LED system is suitable as an illumination system for plants to supplement natural light without substantially interfering with the amount of natural light. The system delivers uniform illumination and reduces energy and maintenance costs.