Excellent light quality for plant growth was attained in the new Davis campus phytotron (described in the November 1961 issue of California Agriculture) through the use of prismatic glass blocks to direct sunlight downward onto the growing benches—plus supplemental light when needed from photocell-controlled electric lamps. This article details preliminary experiments with plant growth in the large, early model phytotron, including comparisons with plant growth in conventional greenhouses.

Financial aid from the National Science Foundation, Facilities and Special Programs, is gratefully acknowledged. Numerous individuals from many plant science departments contributed plants for the first experiment reported.