I think blue and red light of the spectrum are the most important for plant growth because these wavelengths are critical for photosynthesis. Blue light (around 400-490 nm) is essential for vegetative growth, promoting strong leaf development and overall plant health. It also influences the plant's growth patterns and helps in the production of chlorophyll.
Red light (around 620-750 nm) is crucial for flowering and fruiting processes. It stimulates the production of phytochromes, which are proteins that help regulate various developmental processes in plants, including germination, flowering, and stem elongation.
Together, blue and red light create optimal conditions for photosynthesis, enabling plants to convert light energy into chemical energy more efficiently, which ultimately supports healthy growth and development.