The invention relates to a self-contained watering device allowing to increase the time during which the plant boxes with water reserve or simple pots immersed in containers contain water. The device is based on the principle of communicating vessels with equal levels and its operation is facilitated by a priming system. One of the main characteristics is that a perfect sealing of all connectors or pluggable orifices is not indispensable. The device is comprised of a main container (6), a pipe (5) through which air is sucked or blown in order to prime the connection pipes (4) connected in the reserves of the plant boxes. The device may be completed by one or a plurality of annex container or containers (25) and by many other options improving its performances, the whole assembly being entirely made of plastic material. The invention is mainly intended to domestic use.
