Light Spectrum

Light spectrum refers to the wavelengths of electromagnetic radiation used in cannabis cultivation, typically divided into UV, visible (blue and red), and infrared ranges. Different wavelengths influence plant physiology, morphology, and secondary metabolite production during vegetative and flowering phases. Blue spectrum light (400-500nm) is commonly associated with compact growth and leaf development, while red spectrum light (600-700nm) with flowering and fruiting responses. Breeders and cultivators working in controlled environments use spectrum composition to select for traits like branching patterns, flowering speed, and terpene expression. Understanding spectrum effects helps contextualize how phenotypes may vary between outdoor (full natural spectrum) and indoor (filtered/LED spectrum) growing conditions.

Breeders optimizing for specific plant architectures or secondary metabolite profiles often evaluate parental lines and crosses under controlled light spectra to identify stable, consistent traits independent of environmental variables. Spectrum standardization in breeding programs ensures phenotypic data is reproducible and comparable across generations.