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 for plant growth as it affects transpiration and nutrient uptake.

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 water vapor pressure and the saturation water vapor pressure at a particular temperature.

3. Importance of VPD Calculation

Details: VPD is critical for optimizing plant growth conditions. It helps growers maintain ideal humidity levels to maximize photosynthesis while minimizing disease risk.

4. Using the Calculator

Tips: Enter Saturation Vapor Pressure in kPa and Relative Humidity in percentage (0-100%). Both values must be valid (SVP > 0, RH between 0-100).

5. Frequently Asked Questions (FAQ)

Q1: What is the ideal VPD range for plants?
A: Optimal VPD ranges vary by plant species and growth stage, but generally 0.8-1.2 kPa for vegetative growth and 1.0-1.5 kPa for flowering.

Q2: How does temperature affect VPD?
A: Warmer air can hold more moisture, so temperature affects SVP which directly impacts VPD calculations.

Q3: Why is VPD important for plant growth?
A: VPD affects stomatal opening, transpiration rates, and nutrient uptake - all critical for plant health and growth.

Q4: What happens when VPD is too high or too low?
A: Too high causes excessive transpiration and stress; too low reduces transpiration and nutrient flow, increasing disease risk.

Q5: Can I use this calculator for any plant type?
A: Yes, but different plants have different optimal VPD ranges you should research for specific species.