Diurnal Temperature Range

Diurnal Temperature Range (DTR) refers to the difference between a cannabis plant's daytime high and nighttime low temperatures within a 24-hour cycle. Breeders and cultivators track DTR because it influences plant metabolism, flowering timing, and terpene expression. Most cannabis cultivars show adaptive responses to consistent DTR patterns, with some lineages demonstrating preference for wider ranges (15–25°C differential) while others perform better under minimal fluctuation. DTR becomes particularly relevant in outdoor and greenhouse cultivation where environmental conditions naturally vary, whereas controlled indoor environments allow precise DTR manipulation. Historical breeding records frequently document DTR stability as a selection criterion for regional adaptation and photoperiod sensitivity.

Breeders working in outdoor-adapted lineages often select for cultivars that tolerate or exploit natural DTR cycles, as this trait correlates with phenotypic stability and consistent cannabinoid/terpene profiles across seasons. DTR sensitivity can be a secondary selection marker when stabilizing photoperiod-dependent flowering responses.