Blue boost: Monochromatic blue light and blue-enriched spectra (RBW) enhance physiology, bioactive compounds, and yield of strawberry in indoor vertical farming.

The demand for sustainable foods has driven indoor vertical farming, where strawberry-a high-value crop-responds strongly to light spectral quality. Blue, red, and RBW spectra regulate photosynthesis, morphogenesis, and bioactive compound synthesis. The strawberry cultivar Fragaria × ananassa 'Albion' was grown in an indoor vertical farming system under controlled temperature and humidity using a vertical aeroponic setup. Plants were exposed to four light spectra (white, red, blue, and RBW) and two light intensity regimes-constant and sinusoidal-to evaluate physiological, biochemical, yield, and phytochemical responses. Blue light increased chlorophyll a content and yield, while RBW lighting-particularly under a sinusoidal regime-improved photosynthetic balance, water use efficiency, fruit structure, and weight. Red light enhanced vegetative growth and fruit color and pH, but showed lower photosynthetic efficiency despite higher photochemical yield and SOD and CAT activity. Sinusoidal regimes, especially with RBW, promoted heavier, more intensely colored fruits and increased bioactive compounds, with spectrum-specific accumulation of gallic acid, rutin, cyanidin, kaempferol, quercetin, and catechin. Specific light spectra, especially RBW, improve strawberry physiological performance and fruit quality by increasing bioactive compounds, reinforcing vertical farming as a sustainable and high-performance production system.