1. What is Vapor Pressure Deficit?

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 an important metric in agriculture and climate 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 moisture in the air.

3. Importance of VPD Calculation

Details: VPD is crucial for understanding plant transpiration rates, greenhouse climate control, and assessing environmental stress on plants.

4. Using the Calculator

Tips: Enter SVP in kPa (typically between 0.5-5 kPa for most agricultural applications) and RH as a percentage (0-100%).

5. Frequently Asked Questions (FAQ)

Q1: What are typical VPD values for plants?
A: Most plants thrive at VPD values between 0.8-1.2 kPa, though optimal ranges vary by species and growth stage.

Q2: How does temperature affect VPD?
A: Temperature affects SVP - warmer air can hold more moisture, increasing potential VPD at the same RH.

Q3: Why use kPa instead of hPa?
A: This calculator uses kPa as it's the standard SI unit for pressure in European scientific contexts.

Q4: When is VPD most important?
A: VPD is particularly important in controlled environments like greenhouses and indoor growing facilities.

Q5: How does VPD affect plant growth?
A: High VPD can cause excessive transpiration and stress, while low VPD can limit transpiration and nutrient uptake.