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 key measurement for understanding plant transpiration and growth conditions.

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 crucial for optimizing plant growth conditions, managing greenhouse environments, and understanding evapotranspiration rates in agricultural settings.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What are typical VPD values for plant growth?
A: Optimal VPD ranges vary by plant species but generally fall between 0.8-1.2 kPa for most crops during the day.

Q2: How does temperature affect VPD?
A: Warmer air can hold more water vapor, so SVP increases with temperature, which affects VPD calculations.

Q3: Why is VPD important in agriculture?
A: VPD directly affects plant transpiration rates, nutrient uptake, and overall plant health and growth.

Q4: What's the relationship between VPD and RH?
A: While RH measures current water vapor relative to maximum at current temperature, VPD measures the "drying power" of the air.

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