Abstract: A method and apparatus for growing plants by controlling growing temperatures in conventional and hydroponic planting systems. Plants placed in a plant growing medium are contained in metal growing trays placed in contact with a closed metal piping system and disposed externally to and structurally supporting the growing trays and containing a temperature-controlled liquid, thereby providing conductive heat exchange with the plant growing trays and plants. The plants are also supplied with liquid nutrients and artificial light conductive to plant growth.

Abstract: An indoor lighting arrangement employing a combination of high pressure sodium (HPS) light sources, which produce a yellowish light, and mercury vapor or metal halide light sources, which produce a whiter light. Where the distance between the floor and the plane containing the light sources is at least fifteen feet, the HPS and whiter light sources are mounted in a checkerboard pattern so that the yellow and white illumination which they produce is completely mixed at normal eye level. When lower ceiling heights are involved, lighting fixtures are used which each contain both an HPS lamp and a whiter light lamp.