The impact of LED lighting on the yield, morphological structure and some bioactive components in alfalfa (Medicago sativa L.) sprouts

•The spectrum of visible light affects the chemical composition of cultivated sprouts.•Light color temperature significantly affects mass percentage of cotyledons.•RGB light led to the highest content of chlorophylls, carotenoids and polyphenols.•RGB LED lighting is the best on the content of bioactive compounds of sprouts.•Dispersed sunlight increases the synthesis of vitamin C in alfalfa sprouts.