Temperature Humidity Vapor Pressure Deficit

Vapor Pressure Deficit (VPD) is not an aroma itself, but a cultivation microclimate metric that influences volatile compound expression in cannabis. VPD describes the difference between air moisture saturation at a given temperature versus actual humidity present; it directly affects stomatal function and terpene volatility during growth and flowering. Breeders and cultivators monitor VPD because plants under stress from suboptimal VPD (too dry or too humid) often show altered secondary metabolite profiles, including terpene concentration and composition. Optimal VPD ranges are commonly associated with more consistent aroma development across phenotypes, while extreme VPD conditions may suppress or amplify certain volatile profiles.

Breeders working in controlled-environment programs track VPD data alongside terpene sampling to establish stability benchmarks for a strain. Understanding how a lineage expresses aromatics under varying VPD conditions helps identify phenotypes with robust, climate-resilient terpene production.