Light Spectrum

Light spectrum refers to the wavelengths of light that cannabis plants receive during their growth cycle, ranging from ultraviolet (UV) through visible light to infrared. Different wavelengths—particularly blue (400-500nm) and red (600-700nm)—influence plant development, branching patterns, and secondary metabolite production. Breeders and cultivators manipulate light spectrum to shape plant morphology and potentially influence terpene expression, though direct causal links remain an active area of horticultural research. The term "light spectrum" is sometimes conflated with aroma profiles in breeding discussions, though it describes environmental conditions rather than inherited chemical traits. Understanding spectrum effects helps breeders select parents likely to express desired characteristics under controlled conditions.

Breeders use controlled light spectra during selection to encourage desired plant structures and cannabinoid/terpene patterns in candidate parents. This environmental control is essential for consistent phenotype expression across generations, allowing breeders to reliably identify which genetic traits breed true versus those dependent on cultivation conditions.