The invention provides an illumination arrangement (1) for illuminating horticultural growths (100) with for instance LEDs as a light source. These LEDs are placed in a lighting unit (10). The lighting unit may especially have the ability to direct substantially all light from the light source (here the LEDs) to the horticultural growths (in the greenhouse). Additionally, a horticultural growth-recognition system (50) can be implemented in the illumination arrangement, so that the system can adapt for instance its beam (11) to the location of the horticultural growth(s) (in the case of growth or moving of plants, etc).
