Grow Tent Temperature and Humidity Chart by Stage
Climate is the cheapest yield increase available to a home grower. These are the ranges to hold, lights on, at canopy height.
The targets
Measure at canopy level, not at the floor and not at the top of the tent.
- Seedling: 72-78°F, 65-70% RH
- Vegetative: 72-82°F, 55-65% RH
- Early flower: 72-80°F, 50-55% RH
- Late flower: 68-78°F, 45-50% RH
- Dry: 60-65°F, 58-62% RH
- Cure: 62-70°F, 58-62% RH in jars
Why humidity drops as you go
Young plants have small root systems and transpire through their leaves, so they want humid air. Dense flowers trap moisture and rot, so late flower wants dry air with strong movement. The whole curve exists to match the plant's water strategy and to stay ahead of mold.
Lights-off matters too
Aim to keep lights-off temperature within 10-15°F of lights-on. A bigger swing spikes relative humidity and drives condensation onto cold leaf surfaces, which is how bud rot starts.
Frequently asked questions
- What if I can only control one of the two?
- Control humidity in flower and temperature in veg. Late-flower humidity is the variable most likely to cost you an entire harvest.
Keep reading
Legal notice: We do not promote or encourage breaking the law. This site is for adults 21+ growing in states and jurisdictions that have legalized cannabis cultivation, and who are following all legal growing guidelines, plant count limits, and permit requirements that apply to them.