A cultivation floor system has a floor on which plant containers are to be placed. The system includes a watertight basin and a water-permeable structure in the basin, which structure has a permeable top cloth which forms the top side of the floor on which plant containers are placed. The structure includes one or more water-retaining layers. A watering installation supplies water so that water is available for the plants in the plant containers. A perforated film is placed between the permeable top cloth on the one hand and the one or more water-retaining layers on the other hand, which perforated film is made of impermeable film material which is provided with distributed perforations in such a manner that the film reduces the free evaporation surface for water from the one or more water-retaining layers.