Abstract: A hydroponic apparatus comprising: (a) troughs (12, 13, 14, 15, 16) linked together to form a continuous track located on guide wheel members (24, 26, 28, 30) in a support frame (32, 34), (b) a liquid supply means (36) to supply liquid to the troughs (12–16), wherein, in operation, the addition of liquid to one/some of the troughs (12–16) alters the weight distribution of the troughs (12–16) causing the track to move on the guide wheel members (24, 26, 28, 30) and thus allowing the troughs (12–16) which have become lighter as liquid is consumed by the plants and/or is lost through evaporation to move into position to be replenished with liquid. This movement is a continuous cycle according to changes in the weight distribution of the troughs (12–16) as liquid is being consumed and replenished.