SEED PRODUCTION OF PERENNIAL GRASSES IN THE GREENHOUSE

Satisfactory seed production of several perennial grasses was obtained in the greenhouse in winter by using low temperatures and supplementary fluorescent lighting. Increasing light intensities from 400- to 800-foot candles approximately doubled seed production when lights were used for a 9-hour period. When lights were used for the entire day period of 17 hours, increasing light intensities from 500 to 750 f.c. or to 1,500 f.c. gave non-proportional increases in seed yields. Continuous lighting and 21-hour day lighting were not markedly better than 17-hour day lighting. Incandescent light of 400 f.c. was comparable to an equivalent intensity of fluorescent lighting in promoting seed production but incandescent lighting of 800 f.c. was inferior to 800 f.c fluorescent lighting.