Most indoor growers focus on light and fertilizer. But humidity and temperature are arguably the two most impactful factors for plant growth.
VPD (Vapour Pressure Deficit) measures how much more moisture the air can hold. Ideal range is 0.8–1.2 kPa. Too low = stomata close, growth slows, mold risk increases. Too high = plant loses excess water and stresses.
GrowlyBox DHT22 sensor samples temperature and humidity every second, with real-time alerts via the app.
Humidity management: Increase fan speed to lower humidity. For dry conditions, a small water tray near the cabinet helps.
Day-night temperature difference (DIF): Dropping temperature 2–4°C at night improves fruit flavor and supports natural plant rest cycles.