Question 1

What is Vapor Pressure Deficit (VPD)?

Accepted Answer

VPD is the pressure difference between leaf interior humidity (100% saturation) and the surrounding air. It indicates how hard a plant is transpiring to pull water and nutrients.

Question 2

What is an ideal VPD for vegetative growth?

Accepted Answer

For vegetative growth, aim for a VPD of 0.8 to 1.1 kPa. This moderate pressure keeps stomata open for gas exchange without causing transpiration stress.