Abstract: Water or air is directed through a hood or double cylinder cooling device for providing cooling to one or more light bulbs used in growing plants in greenhouses, aquarium, and hydroponic applications. A water recirculation system with a reservoir and a pump may provide a flow of cooling water through tubing to the hood. The hood provides a housing and a tube which contains one or more light bulbs which can be accessed or replaced through an end of the tube which projects through the housing. The light holder includes an enclosed electric box and a plurality of curved fins which expand against the inside glass tube. Various reflector housing shapes and reflectors direct light to plants. The end cap is bolted to a split ring flange attached to the outer tube.