Cold Stress Coloration

Cold stress coloration refers to anthocyanin and carotenoid pigmentation that emerges in cannabis plants exposed to low temperatures, typically below 50°F (10°C). These water-soluble and fat-soluble pigments—distinct from chlorophyll—produce purple, red, blue, and orange hues in leaves, stems, and occasionally flowers. Expression varies significantly by genotype; some cultivars show pronounced color shifts while others remain green regardless of temperature. Cold stress coloration is a phenotypic response rather than a heritable trait, though genetic predisposition to pigmentation intensity is well-documented across breeding lines. Understanding this response helps breeders select parents with visible anthocyanin potential and informs cultivation protocols in cooler climates.

Breeders working in cooler regions or targeting ornamental/novelty markets often select parent plants that reliably express cold-induced pigmentation. While coloration itself doesn't confer agronomic advantage, the underlying genetic capacity for anthocyanin production is tracked as a secondary trait in multi-generational crosses.