Temperature Humidity Vpt

Temperature, humidity, and vapor pressure deficit (VPD) form an interconnected environmental triad that significantly influences cannabis plant physiology and development. VPD—the difference between the amount of moisture in the air and the maximum amount the air can hold at a given temperature—directly affects stomatal function, nutrient uptake, and transpiration rates. Breeders and cultivators working with specific genotypes have observed that plants express distinct phenotypic characteristics under varying VPD conditions, including leaf morphology, internode spacing, and flowering timing. Understanding this relationship is essential for stabilizing traits across growing environments and predicting how a cultivar will perform under different climate parameters. Lineage records frequently document that cultivars developed in particular climate zones may require environmental adjustment

Breeders working to stabilize phenotypes for commercial environments prioritize selecting parent plants that demonstrate consistent expression across a range of VPD conditions. Detailed environmental logging during breeding cycles helps identify whether desirable traits—such as resin production, branching structure, or flowering duration—are genetically fixed or environmentally dependent, informin