A cultivation floor system with a floor includes a watertight basin with a watertight groundsheet, a water-permeable structure in the basin, and a permeable top sheet which lies substantially horizontally over the water-permeable structure and forms the top side of the floor on which plant containers are optionally placed. The basin has a water-barrier structure which protrudes above the floor and delimits the compartment which is present on the floor. The water-barrier structure includes a horizontal beam with a top side, a water-barrier profile with a bottom side, and fastening means which fasten the water-barrier profile to the horizontal beam. The top side of the beam is substantially level with the top side of the floor formed by the permeable top sheet. The bottom side of the water-barrier profile is pulled onto the top side of the horizontal beam while clamping the watertight groundsheet and the permeable top sheet.