Air pulsed hydroponic unit

Claim 1

A hydroponic unit comprising: a tray for holding aggregate; at least one drainage aperture in said tray; a reservoir for nutrient solution arranged to hold nutrient solution between a predetermined lower level and a predetermined upper level; said upper level being below the level of aggregate in said tray; said reservoir being located to receive liquid passing downwardly through said drainage aperture; a liquid conduit having a lower end open in the reservoir below said lower predetermined level, and an upper end having at least one aperture opening into said tray; said liquid conduit including an extent continuously rising from below said lower predetermined level to a location as high as said at least one aperture which opens into said tray; the cross-section of said liquid conduit being chosen so that air bubbles may extend across the cross-section of the tube; an air conduit introduced into the liquid conduit through the lower open end of the liquid conduit, said air conduit having an open end located in said liquid conduit below said lower predetermined level in a portion of said continuously rising extent whereby bubbles created by air released by the air conduit, rise in said extent.