A pot (40) shown having a well formed by a side wall connecting a base wall aperture (43) and internal aperture (44). A mesh (42) is provided to retain liquid transferring material. The invention provides a liquid transfer means for transferring liquid between growth medium and a local environment external to the pot and adjacent the base wall, the liquid transfer means transferring liquid to in or from an internal zone in the chamber wherein the internal zone is spaced from the bottom wall. Alternative embodiments provide a solid liquid permeable plug (20) which may be inserted in a tight nesting fitting through a bottom wall aperture (21) or through a well (36). Alternatively, a wick arrangement (56) may be provided to insert through a well or a side wall aperture (65) and extending into the internal zones. The conduit may be formed as a slot (52). A cap (54) may be optionally be provided. The invention extends to a method of water control and a system for controlling a plurality of pots according to the disclosure. The pots may be located on a capillary mat (68) and in liquid communication therewith to transfer a liquid to and/or from the internal zone in the base of the pot. The pot base is preferably planar externally to provide an easy working surface.