What is VPD (Vapor Pressure Deficit)?

Vapor Pressure Deficit (VPD) is a crucial concept in controlled environment agriculture that measures the difference between the amount of moisture in the air and how much moisture the air can hold when saturated.

Why VPD Matters

• Yield quality and quantity

How to Calculate VPD

The formula for calculating VPD is:

VPD = SVP - (RH × SVP / 100)

• RH = Relative Humidity

Target VPD for Different Growth Stages

• Target VPD: 0.8-1.2 kPa

• Target VPD: 1.2-1.6 kPa

How to Lower VPD

If your VPD is too high, you can lower it by:

Increasing humidity: Add a humidifier

Decreasing temperature: Adjust your climate control

Improve air circulation: Better airflow

Common VPD Mistakes to Avoid

Ignoring temperature: VPD depends on both temperature and humidity

Not monitoring regularly: Conditions change throughout the day

Following generic charts: Different plants have different optimal VPD ranges

• Charts: VPD charts for quick reference

Conclusion

Optimizing VPD is one of the most effective ways to improve your grow. By maintaining the right VPD, you ensure your plants can efficiently transpire and take up nutrients, leading to healthier plants and better yields.

Start monitoring your VPD today and watch your plants thrive!