Vpd Vapor Pressure Deficit

Vapor Pressure Deficit (VPD) is not an aroma or flavor compound, but rather an environmental measurement critical to cannabis cultivation science. VPD quantifies the difference between moisture the air can hold versus what it actually contains, expressed in kilopascals (kPa). Growers monitor VPD to optimize transpiration rates, nutrient uptake, and secondary metabolite production—including aromatic terpene expression. Cannabis plants commonly show enhanced terpene volatilization and resin development within VPD ranges of 0.8–1.5 kPa during vegetative growth and 0.4–1.0 kPa during flowering. Understanding VPD helps breeders and cultivators predict how environmental conditions influence phenotypic expression of aroma profiles across genotypes.

Breeders working in controlled environments use VPD data to standardize cultivation protocols, ensuring consistent terpene and cannabinoid expression across seed lots. By documenting VPD conditions during parent plant selection and offspring evaluation, breeders can identify genetic lines with stable aromatic output under specific climate conditions.