Abstract: Apparatus is disclosed which provides for the efficient self-watering of plants from a moving flow of water in a display unit tray. The watering apparatus includes an interior upright drain conduit disposed within the tray. This conduit includes drain aperatures providing a continual first flow of water from the tray. A cap including a top and a skirt extending downwardly substantially perpendicular to the top is disposed on the conduit and is movably adjustable thereon. A plurality of aperatures extend through the skirt of the cap and communicate with the conduit to provide a selectively varied record flow of water from the tray in conjunction with a relieved portion on the conduit which selectively communicates with the plurality of aperatures extending through the skirt of of the cap.