An installation such as, for example, a box or cabinet for horticultural applications includes a lighting space between a lighted plane and a lighting plane parallel to the lighted plane, with side walls that are at least partly light-reflective. The illuminated plane may be defined by the upper surface of a plant culture medium. A set of light radiation sources, e.g. LEDs, arranged centrally relative to the lighting plane projects light radiation towards the lighted plane in the direction of a radiation emission axis. The set of light radiation sources emits light radiation with a distribution of illuminance projected towards the lighted plane, wherein the lighted plane is non-uniform and gradually decreases as a function of the angle relative to the aforesaid radiation emission axis, wherein the reflection of the radiation on the side walls facilitates uniform illuminance at the lighted plane.
