Effect of supplemental lighting on cucumber as affected by different levels of light transmission reduction in a greenhouse

Abstract

This study was conducted to compare the growth and yield of cucumbers with and without supplemental lighting (SL) in a low-light intensity inside a greenhouse due to particulate matter (PM). Cucumber (Cucumis sativus L. 'Sindong') seedlings were transplanted into the pots filled with a commercial growing medium. The reduction rates of light transmission in the greenhouse were set to 0, 10, 20, and 30%, respectively. The supplemental light source used a white light-emitting diode (red: green: blue = 5:3:2). SL was conducted after sunrise for 4 h with a light intensity of 150 +/- 20 mu mol<middle dot>m(-2)<middle dot>s(-1). As light transmittance decreased inside the greenhouse, cucumber growth and yield decreased. In particular, the growth and yield of cucumbers were the lowest in the treatment with a light-transmission reduction rate of 30% but were significantly increased through SL. Additionally, the fruit length, diameter, and fruit fresh and dry weights tended to decrease as the light transmittance reduced but significantly increased through SL. The results of this study can be used as basic research data to investigate the effects of SL to improve the growth and yield of cucumber.