Enhancing the vase life of cut roses through spectral optimisation during greenhouse cultivation

Abstract Supplemental lighting is essential for maintaining the marketable quality of greenhouse‐grown roses during periods of limited ambient light. Here, we investigated the effects of three red‐to‐blue (R‐to‐B) light emitting diode (LED) spectral combinations—90:10, 80:20 and 70:30—on key physiological traits and postharvest performance in two cut rose cultivars cultivated under suboptimal natural light conditions. All supplemental lighting treatments improved photosynthetic efficiency, with the 90:10 R‐to‐B ratio showing the most consistent and pronounced effects. This red‐dominant spectrum significantly increased levels of chlorophylls, carotenoids, anthocyanins and both soluble and insoluble carbohydrates, suggesting enhanced source strength and antioxidative potential. Stomatal analysis revealed that while all treatments increased stomatal density, the 90:10 R‐to‐B ratio uniquely induced smaller pore apertures and distinct morphological changes, likely contributing to reduced transpirational losses and an extension of vase life by up to 30% compared to conventional lighting. Genotypic differences in stomatal traits, pigment composition and carbohydrate partitioning were evident, highlighting cultivar‐specific responses to spectral inputs. These results demonstrate how tailored light spectra can improve physiological status at harvest and postharvest resilience, marking a significant step forward for precision horticulture and floriculture. Future research should assess long‐term effects across diverse cultivars and production cycles to support commercial scalability and economic feasibility.