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Tools

Vapor Pressure Deficit Calculator

How strongly the air is pulling moisture out of the crop, expressed as a pressure rather than a percentage.

What VPD describes

Relative humidity means something different at every temperature. VPD expresses the gap between the moisture the air holds and the maximum it could hold at that temperature, in kilopascals. That gap drives transpiration, and with it water movement and nutrient uptake through the plant.

Where it is used

  • Setting and reviewing climate setpoints
  • Understanding crop water demand across the day
  • Managing humidity in relation to disease pressure

How the calculator works

Enter a temperature and relative humidity with a minimum and maximum temperature. The tool returns a grid of VPD values across that range. Temperature can be entered in Celsius or Fahrenheit.

Contact

Reviewing a climate strategy?

Humidity connects to irrigation, crop load and system design.