Abstract: An evaporative cooling chamber useful for growing plants produced from in vitro cultures includes a floor constructed of cotton matting to permit liquid water to be brought into capillary contact with plant material placed thereon, sidewalls of cheesecloth or saran extending vertically upward, a water delivery system of ooze piping for delivering water along the top edges of the side walls, including a water supply trough for feeding the ooze piping and a translucent roof member adapted to receive water of condensation formed within the chamber and to deliver the condensed water to the water supply trough for recirculation and continuation of the evaporative cooling process.