The Effect of LED Lighting on Growth and Fruit Quality of Melon (Cucumis Melo L.) Grown in Plastic House

Abstract

Controlled cropping of orange-fleshed melon cv. Amy KT 22 in plastic houses with white light emitting diodes (LED) lighting was conducted to study the effect of white light LED lighting time on the growth and fruit quality of melons. Three treatments were tested: natural daylight (NDL, control), NDL plus 6 h LED (6:00 pm to 12:00 pm), and NDL plus 12 h LED (from 6:00 pm to 6:00 am). LED supplemental lighting was applied daily. The results showed that melon growth measured as plant height remarkably increased with LED lighting. The 6 h duration was sufficient as the longer duration of 12 h had no corresponding significant effect. This was obtained starting after 3 weeks from transplanting (WFT) and weekly thereafter up to the end of the observation period (8 WFT). Leaf chlorophyll content was significantly higher in plants receiving 12 h LED lighting than that of the control but only after 7-8 WFT. In terms of fruit attributes, only peel thickness was significantly affected, with the 6-12 h LED lighting resulting in a thicker peel than the control. LED lighting did not significantly improve fruit weight, size, flesh thickness, color (L*, a*, and b*), firmness, juice pH, total soluble solids (TSS), and titratable acidity (TA) relative to the control. Additional white LED lighting for 6 and 12 hours significantly affected melon growth. However, in terms of the fruit quality, adding LED lighting gave no different results than growing only under natural light. Thus, the use of LED lighting to increase the efficiency of melon fruit production may not be necessary. It might be adapted to plants where leaves and stems are commonly consumed.