1. What is Vapor Pressure Deficit (VPD)?

Vapor Pressure Deficit (VPD) is the difference between the amount of moisture in the air and how much moisture the air can hold when it's saturated. It's a crucial measurement in agriculture and environmental control.

2. How Does the Calculator Work?

The calculator uses the VPD equation:

Where:

• \( SVP \) — Saturation Vapor Pressure (kPa)
• \( RH \) — Relative Humidity (%)

Explanation: The equation calculates the difference between the actual and potential water vapor in the air.

3. Importance of VPD Calculation

Details: VPD is critical for plant growth as it affects transpiration rates. Proper VPD levels help optimize plant growth and prevent stress.

4. Using the Calculator

Tips: Enter SVP in kPa and RH as a percentage (0-100%). Both values must be valid (SVP > 0, RH between 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What are ideal VPD ranges for plants?
A: Typically 0.8-1.2 kPa for most plants, but varies by species and growth stage.

Q2: How does temperature affect VPD?
A: Warmer air can hold more moisture, so temperature affects SVP and thus VPD.

Q3: Why use VPD instead of just RH?
A: VPD accounts for both temperature and humidity, giving a more complete picture of plant stress potential.

Q4: What tools measure VPD?
A: Specialized environmental controllers or combined temperature/humidity sensors with VPD calculation.

Q5: Can VPD be too high or too low?
A: Yes, both extremes can stress plants - high VPD causes excessive transpiration, low VPD can lead to poor nutrient uptake.