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 cannabis cultivation environments.

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: Proper VPD levels are essential for optimal cannabis growth, affecting transpiration rates, nutrient uptake, and overall plant health. Ideal VPD ranges vary by growth stage.

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 is the ideal VPD range for cannabis?
A: Generally 0.8-1.2 kPa for vegetative stage and 1.0-1.5 kPa for flowering stage, but optimal ranges may vary.

Q2: How does VPD affect cannabis plants?
A: VPD influences stomatal opening, transpiration rates, and nutrient uptake, directly impacting plant growth and health.

Q3: When should I measure VPD?
A: VPD should be monitored continuously throughout the day as temperature and humidity fluctuate.

Q4: Are there limitations to VPD calculation?
A: VPD doesn't account for all environmental factors and should be used alongside other measurements like temperature and CO2 levels.

Q5: How can I adjust VPD in my grow space?
A: Adjust temperature, humidity, or both to achieve optimal VPD ranges for your plants' growth stage.