Long Day Dependent

Long Day Dependent (LDD) refers to cannabis plants that require extended light periods—typically 14+ hours daily—to initiate and complete flowering. This classification is rooted in photoperiod sensitivity, distinguishing these cultivars from short-day dependent (SDD) varieties that flower under shorter light cycles. LDD genetics are less common in commercial cannabis breeding, as most cultivated strains have been selected for shorter flowering triggers. Lineage records indicate LDD traits may persist in landraces or heritage genetics originating from regions with naturally extended growing seasons. Understanding photoperiod classification remains essential for controlled-environment cultivation planning and breeding program development.

Breeders working with LDD genetics typically employ them in research or specialty programs exploring photoperiod diversity and environmental adaptation. These traits can be crossed into conventional breeding lines to study how light-sensitivity genes interact with other desired characteristics, though LDD plants generally require additional infrastructure or extended light cycles compared to SDD v