The Effect of Relative Humidity on Growth, Yield, and Water Consumption of Bean Plants1

Abstract

Abstract Red kidney bean ( Phaseolus vulgaris L.) plants were grown continuously under 35-40%, 70-75%, or 95-100% relative humidity in growth chambers. There were no significant differences in fresh or dry weight of plants after 20 or 26 days’ growth in the chambers. Water consumption was significantly lowered by the highest humidity, and the dry weight produced per unit of water consumed was significantly greater in those plants grown at 95-100% relative humidity. After 47 days at the stated humidity levels, no significant differences were found in fresh or dry weight of the fruits. The only significant difference in seed dry weight was between the lowest and the medium humidity. The yield in the low humidity was 60% of that in the medium humidity. Thus, there are no significant reductions in either growth or yield of bean plants by continuous growth at near saturation relative humidity.