Potassium Stress Pigmentation

Potassium stress pigmentation refers to anthocyanin and other pigment accumulation triggered by potassium deficiency or restricted availability during flowering and late vegetative stages. Cannabis cultivars expressing this trait develop deep purples, reds, or blues as a metabolic response to nutrient limitation, particularly when night temperatures drop below 15°C. This phenotype is genetically heritable and influenced by both plant genotype and environmental conditions; some cultivars reliably express these pigments under stress, while others remain green regardless. Breeders frequently select for potassium-sensitive pigmentation when stabilizing dark-colored cultivars, though the trait's expression is not guaranteed without proper environmental triggers.

Growers and breeders manipulate potassium availability and temperature to reliably induce or intensify pigment expression in target lines. Understanding which cultivars carry genetic predisposition to this response helps breeders select parents and predict offspring coloration stability across growing conditions.