On the basis of an installation formed from plastic sheets (1), (3), (4), of pairs of parallel, horizontal rods or cables (2), defining several superimposed layers (13-17-18), which are closed by means of an upper cover (5) traversed by the plant stems (9) that are supplied, through a perforated tubing (16), with a nutrient-bearing solution for the plants in a hydroponic cultivation system, the invention consists of substantially filling the upper level (13) with a natural cultivation substrate mass (14) such that the plants basically take root on said substrate (14), extracting the nutrients both from the substrate mass and from the solution provided, with controlled nutrient layers. A second tube (19) allows the supply of gases for oxygenation, carbon fertilisation or disinfection, which reaches all levels (13-17-18) of the installation through the nutrient solution overflow orifices (10) and (12).