A hydroponic system (100) is provided with a cultivation vessel (7) that includes at least some of plants (8), a fluid fertilizer spray unit (5a) for spraying a fluid fertilizer (50) to a space inside the cultivation vessel (7) so as to supply the fluid fertilizer (50) to at least some of the plants (8), a cleaning fluid ejection unit (3a) for ejecting a fluid for cleaning to the space inside the cultivation vessel (7) so as to clean at least some of the plants (8) and/or the inner surface of the cultivation vessel (7), and a discharge passage (30) for guiding the fluid fertilizer (50) and the fluid for cleaning from the cultivation vessel (7) to the outside of the cultivation vessel (7).
