Light. Data. Growth. Smarter cultivation starts here.
VPD (Vapor Pressure Deficit) helps you fine-tune your grow room's temperature and humidity for ideal plant transpiration and nutrient uptake.
Ideal VPD ranges: Seedlings: 0.4–0.8, Veg: 0.8–1.2, Flower: 1.2–1.6 kPa.
VPD Calculator for Cannabis Growers
Enter your temperature and humidity to estimate your Vapor Pressure Deficit.
Want to understand what your VPD result means? Read our VPD guide →
Need a Quick Reference? View the VPD Chart Below
Cannabis VPD Chart (°F & RH)
Use this chart to find the ideal Vapor Pressure Deficit (VPD) for your temperature and humidity. The green zone is optimal for growth!
| Temp (°F) | 40% RH | 50% RH | 60% RH | 70% RH | 80% RH |
|---|---|---|---|---|---|
| 68°F | 1.10 | 0.92 | 0.73 | 0.55 | 0.37 |
| 72°F | 1.23 | 1.03 | 0.82 | 0.62 | 0.41 |
| 75°F | 1.32 | 1.10 | 0.88 | 0.66 | 0.44 |
| 78°F | 1.42 | 1.18 | 0.95 | 0.71 | 0.47 |
| 82°F | 1.56 | 1.30 | 1.04 | 0.78 | 0.52 |
Chart values are approximate. Use the VPD Calculator for exact results.
Frequently Asked Questions
Q: What is VPD?
A: VPD stands for Vapor Pressure Deficit. It measures the drying power of air and helps you balance temperature and humidity for ideal plant transpiration.
Q: What’s a good VPD?
A: Seedlings like 0.4–0.8 kPa, veg plants prefer 0.8–1.2 kPa, and flowering plants thrive between 1.2–1.6 kPa.
Q: How do I raise my VPD?
A: Increase temperature or lower humidity. Use a dehumidifier or adjust your exhaust fan setup.
Q: What if my VPD is too high?
A: Lower temperature or increase humidity. Add a humidifier or reduce ventilation temporarily.
Q: What tools help manage VPD?
A: Use a thermometer + hygrometer, humidifier, dehumidifier, and smart controller to monitor and automate your climate.
Tool by GrōHaus — helping growers dial in their light, space, and yield.