VPD: Vapor Pressure Deficit

Targets:

• Clones: .6-.8
• Veg: .9-1.1
• Flower: 1.2-1.5

VPD Notes:

• Many nutrients (Ca) are moved into a plant through the plant's transpiration stream, so temperature and humidity will impact uptake
• Trust the VPD chart
• Understanding VPD will help you understand your plants even if you can't impact those variables