Magnesium Lockout

Magnesium lockout is not a terpene, but rather a plant physiology condition where cannabis cannot absorb available magnesium from soil or growing medium, despite adequate magnesium presence. This occurs when pH levels, nutrient ratios, or ion concentrations interfere with magnesium uptake by roots. Growers and breeders observe lockout symptoms—typically interveinal chlorosis on older leaves—as a diagnostic indicator of cultivation problems rather than a genetic trait. Understanding lockout mechanisms is relevant to breeding programs selecting for nutrient efficiency and stress resilience.

Breeders working with cultivars for controlled-environment production sometimes evaluate lines for apparent magnesium-use efficiency and pH tolerance. Selecting genetics that perform reliably across varying nutrient profiles can reduce production losses in indoor and outdoor systems where pH drift or ion imbalances occur.