A hydroponic conduit can be converted to drainage conduit by providing an attachment on which a plant container can be supported. The attachment comprises a circular plate on which the plant containers sits, drainage means (ribs, grooves etc.) and a central aperture in the circular plate to allow water to drain from the circular plate, and a short collar or spout on the bottom of the circular plate which passes into an opening in the hydroponic conduit to allow water to drain into the conduit. A second support means can be provided which is attached to the hydroponic conduit and which provides additional support to the attachment.