Long Day Responsive Types

Long Day Responsive Types (LDR) refer to cannabis cultivars that exhibit extended vegetative growth periods under lengthening or sustained long photoperiods (16+ hours light daily). These plants delay or suppress flowering onset when exposed to continuous light conditions, contrasting with traditional short-day photoperiodic varieties. Lineage records frequently report LDR traits emerging from equatorial or high-latitude landraces where seasonal daylight variation was minimal or extreme. Breeders working with LDR genetics often seek to create photoperiod-independent or flexible-timing cultivars suitable for extended indoor growth cycles or light-supplemented outdoor production. This family encompasses both accidental discoveries and deliberate crosses designed to decouple flowering from strict 12-hour light triggers.

LDR traits enable indoor cultivators to extend vegetative growth without forced flowering, allowing larger canopy development before bloom transition. Breeders cross LDR backgrounds into traditional short-day lines to create intermediate photoperiod-sensitive hybrids or to explore genetic flexibility in controlled-environment agriculture.