LED lighting and seasonality effects antioxidant properties of baby leaf lettuce

► Antioxidant properties of baby leaf lettuce depend on multicomponent exposure of variety, light quality and growing season. ► Vitamin C, total phenol, tocopherol contents were more enhanced by HPS lighting supplemented with green LEDs than with blue. ► Significant positive effect of supplemental LEDs on DPPH scavenging capacity was in order: 535 = 470 > 505 > 455 nm. ► The similar trend of significant positive effects was observed for total anthocyanins: 505 > 455 > 470 > 535 nm.