Auto-flowering

Auto-flowering — also rendered autoflower or day-neutral — describes Cannabis sativa L. cultivars that transition from vegetative to reproductive growth based on chronological age rather than photoperiod signals, typically 2–4 weeks after germination, completing a full seed-to-harvest lifecycle in approximately 8–12 weeks (Stack et al. 2021; Dowling et al. 2024). The trait is widely attributed to introgression from putative C. sativa subsp. ruderalis (Janischevsky 1924), weedy high-latitude populations adapted to short growing seasons (Small 2015; McPartland 2018). Toth et al. (2022) mapped the causal Autoflower1 locus on chromosome 1 as a recessive Mendelian factor; Dowling et al. (2024) associated it with a FLOWERING LOCUS T ortholog. Lynch et al. (2016) placed autoflower varieties "Lowryder" and "Auto AK-47" in the narrow-leaf drug-type clade with likely ruderalis ancestry. Etymology: English auto- (Greek autos, "self") + flowering. Synonyms/slang: autoflower, auto, day-neutral, photoperiod-insensitive, "ruderalis hybrid." → See also: Photoperiod, Flowering, Seed, Ruderalis.