A plant growing device (1) has been described with a container for feed in water for the plants (2), a container for fertilizer (2a), a container for water (2b), a container for acid (2c) and a mixer； one or more growing trays (3) for one or more plants in a substrate； a tube (6) from said container for feed in water for the plants (2) to the one or more growing trays (3) for the transport of said feed to the plants, and means (7) to condensate the water vapour leading to a tube (8) to lead back the condensed water to the container for water (2b). Furthermore, the application of this device for a method for growing plants. without using a drainage system has been described as well.
