Cold Stratification

Cold stratification is a seed preparation technique where viable cannabis seeds are exposed to prolonged cool, moist conditions—typically 2–8°C for 4–8 weeks—to simulate winter dormancy. This process breaks seed dormancy and can improve germination rates, particularly in heirloom and landrace genetics where natural seasonal cycles shaped reproductive timing. Breeders and seed preservation efforts commonly employ cold stratification to enhance germination uniformity and viability in seed banks. The practice mirrors environmental conditions seeds encounter in temperate growing regions and is especially relevant for genetics adapted to colder climates. Cold stratification does not alter the genetic makeup of seeds; it prepares them for more reliable sprouting.

Breeders working with heritage genetics and cold-adapted cultivars often incorporate cold stratification into breeding stock preparation to ensure consistent germination rates and maintain genetic integrity across generations. This technique is particularly valuable for preserving landrace populations and stabilizing F1 hybrid vigor.