Integrating Environmental Control and Hyperspectral Imaging to Assess Light and Nutrient Effects on Lettuce Post-Harvest Quality in Vertical Farming

33/2026

Integrating Environmental Control and Hyperspectral Imaging to Assess Light and Nutrient Effects on Lettuce Post-Harvest Quality in Vertical Farming

Sunday 12th April 2026

Franzoni, G.; Mirabella, S.;  Dabek, A.; Ferro, N.; Antona, A.; Carlessi, M.; Cinquemani, S.; Matteucci, M.; Cocetta, G.; Perotto, S.

Vertical farming offers an opportunity to optimize crop yield and quality through precise control of environmental factors. In this study, we investigated the effects of light spectrum composition and nutrient solution electrical conductivity (EC) on yield and on biochemical traits of lettuce (Lactuca sativa L. cv. Lollo Rosso) grown in a vertical farm. The experimental design combined three light treatments (high blue, low blue, and variable blue ratio) with three nutrient solution EC levels (1, 2, and 3 dS/m), resulting in nine treatment conditions. Plants were harvested twice, and destructive analyses were conducted at harvest time and after 14 days of cold storage to assess yield, water content, pigments, sugars, nitrates, anthocyanins, phenolics, and electrolyte leakage. Results showed that lettuce growth and quality were influenced by both nutrient solution composition and light spectrum: higher salt concentration enhanced growth but not yield, while blue light promoted plant compactness. Diluted solutions increased secondary metabolites under mild nutrient stress, with limited effects on pigment content, sugar dynamics, and postharvest preservation. As a complementary analysis, hyperspectral imaging (400–1000 nm) was applied to lettuce leaves. Spectral data were analysed using machine learning models to investigate the relationship between changes in reflectance and in chemical composition, by comparing leaves at harvest with those after 14 days of cold storage. The adopted approach demonstrated the feasibility of using hyperspectral imaging to classify lettuce leaves at different post-harvest stages and identified candidate combinations of spectral indices capable of capturing the degradation of specific chemical traits occurring during the storage period. Overall, this study highlights the central role of nutrient solution concentration and light spectrum in determining lettuce yield and quality in vertical farming, while demonstrating the added value of hyperspectral imaging as a supplementary approach for trait assessment.