Temperature Stress Coloration

Temperature stress coloration refers to pigment changes—typically anthocyanins, carotenoids, and chlorophyll degradation—that cannabis plants express when exposed to cool or cold conditions during flowering and late vegetative stages. These shifts range from deep purples and blues to reds and dark browns, and are distinct from genetic color traits. The phenomenon is environmentally triggered rather than genetically fixed, meaning the same cultivar may or may not display these colors depending on growing conditions. Breeders and cultivators often use intentional temperature fluctuations to express latent pigmentation, though the mechanism remains incompletely characterized. Documentation of temperature-induced color expression helps distinguish between inherent pigmentation genetics and environmental response.

Breeders working with purple or dark-pigmented phenotypes must differentiate between stable genetic coloration and stress-induced hues when selecting parent material for consistency. Understanding temperature sensitivity allows cultivators to either stabilize color traits through selection or to manage environmental conditions to express or suppress coloration as desired.