Vapor Pressure Deficit Sensitivity

Vapor Pressure Deficit (VPD) sensitivity describes a plant's phenotypic responsiveness to the difference between air saturation and actual moisture content in a growing environment. Cannabis cultivars exhibit variable tolerance ranges; some genetics maintain vigor across wider VPD fluctuations, while others show stress responses—such as stomatal closure, reduced transpiration, or leaf edge damage—when VPD drifts beyond their optimal window. Breeders and cultivators classify strains along a sensitivity spectrum to predict performance under specific climate conditions. This trait is particularly relevant in controlled-environment agriculture, where VPD management directly influences photosynthetic efficiency, nutrient uptake, and overall phenotypic expression. Documentation of VPD sensitivity has become standard in modern breeding programs seeking environmental resilience.

Breeders working in CEA and greenhouse contexts increasingly select for VPD-tolerant lineages to reduce cultivation complexity and environmental overhead. Strains showing broad VPD adaptation are often crossed to introduce stability into new hybrids destined for variable indoor or semi-controlled settings.