The invention concerns a fitting consisting of a part made of injected plastic for connecting a water tank (1) and a hollow cone (2) made of porous ceramics, so as to produce a device for dispensing water individually to plants, in particular potted plants, proximate to their roots, and in predetermined amount, comprising three coaxial parts a disc-shape intermediate part (4) with a central hole (5) a part (A) consisting of one or two cylinders, arranged on one side of the disc (4) and designed to be permanently fixed to the cone (2) a part (B) consisting like part A of one or two cylinders bearing a thread on the inner surfaces, arranged on the other side of the disc (4) and capable of receiving a bottle (1) removably screwed.