Abstract: Three plant support discs supported by a housing and are rotated so that the intermediate disc is rotated in one direction and the other two discs on either side thereof are rotated in opposite directions so that portions of plants on adjacent discs which overlap one another move in the same direction to cause such portions to gently mesh with one another and avoid damage. A solar cell array provides electrical power for driving an electric motor which in turn drives the discs through a drive train. The discs have projections which pass through slots in gears of the drive train to provide a slidable drive connection between the discs and the gears, while the lower ends of the projections support the discs on a support surface of the housing, thereby minimizing the loading on the gears.