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VPD chart for cannabis – the secret to faster growth
If you want to level up your growing, learn VPD (Vapor Pressure Deficit). It's the relationship between temperature and humidity that controls how fast your plant transpires.
Ideal VPD ranges:
- Seedling: 0.4-0.8 kPa (high humidity, moderate temp)
- Veg: 0.8-1.2 kPa
- Early flower: 1.0-1.4 kPa
- Late flower: 1.2-1.6 kPa (lower humidity to prevent mold)
Quick reference (Temperature → Target Humidity):
- 75°F veg → 65-70% RH
- 78°F veg → 60-65% RH
- 78°F flower → 50-55% RH
- 80°F late flower → 45-50% RH
Dialing in VPD gave me 20% faster growth in veg and noticeably denser buds in flower. Most people just look at temp and humidity separately — VPD is the combo that matters.
There are free VPD calculators online. Start using one! 📊
3 Comments
VPD was the "aha moment" for me as a grower. I was chasing humidity and temp separately for years. Once I started using a VPD calculator app, my plants grew noticeably faster.
For anyone confused: just download a free VPD app, enter your temp and humidity, and it tells you if you're in the green zone. Simple.
20% faster growth is no joke. I saw similar results. The plants just transpire more efficiently when VPD is dialed in. Growth looks more vigorous, leaves are praying, stems are thicker.
Is VPD important for small grows too? I just have a 2x2 tent and can't control humidity very precisely.
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