Temperature Stress Coloration

Temperature stress coloration refers to pigmentation changes that occur in cannabis plants when exposed to cooler nighttime temperatures, typically below 50°F (10°C), particularly during late flowering and final weeks before harvest. This phenomenon involves the expression of anthocyanins and other flavonoid compounds that create purple, blue, pink, or red hues in leaves, bracts, and sometimes flowers. The trait is influenced by both genetic predisposition and environmental conditions—some cultivars are genetically more prone to these color shifts than others. Temperature stress coloration is distinct from baseline pigmentation and represents a dynamic physiological response. Breeders often document this trait when working with parent stock, as it can influence visual phenotype expression across a lineage without necessarily affecting cannabinoid or terpene profiles.

Breeders working with temperature-responsive cultivars track coloration patterns as a phenotype marker and environmental indicator. Some breeding programs intentionally select for or against cold-temperature color expression depending on target market aesthetics and regional growing conditions.