Supplemental lighting and CO₂ enrichment on the growth, fruit quality, and yield of cucumber

We evaluated the effects of supplemental lighting and carbon dioxide (CO₂) enrichment on cucumber growth, fruit quality, and yield. The study was conducted over 43 d in a plastic greenhouse. The plastic greenhouse was divided into two sections; the first section was arranged for supplemental lighting treatment (SL) and ambient lighting (control). The second section was arranged for the simultaneous supplemental lighting and CO₂ enrichment treatment (SL + CO₂). Plant growth, fruit characteristics, fruit yield, and economic statistics were evaluated. In the growth variations of the plants, the number of nodes and stem diameter in SL + CO₂ were significantly higher than that in the control. No significant differences were observed in the final cucumber plant growth. Although there were no significant differences in fruit quality, the dry matter of cucumber fruits increased in the following order: control, SL, and SL + CO₂. SL + CO₂ generally showed a significantly higher average number of female flowers than the other treatments. Consequently, SL + CO₂ showed a 35% increase in yield compared to that of the control. Economic analysis indicated that the income rate for SL was 106% and SL + CO₂ was 111%, both of which were higher than that of the control. Therefore, supplemental lighting and CO₂ enrichment of cucumbers can enhance their initial growth and yield, potentially increasing income for cucumber farms.