Grow Tent Temperature and Humidity Chart by Stage
By The Budometry TeamPublished Updated
Climate is the cheapest yield increase available to a home grower. These are the ranges to hold, lights on, at canopy height.
Part of our pillar guide: Grow Room Climate: Temperature, Humidity, Airflow and Smell
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.
The full guide on this topic
Grow Room Climate: Temperature, Humidity, Airflow and Smell
Stage-by-stage temperature and humidity targets, VPD explained simply, how to size an inline fan, and how a carbon filter keeps a flowering tent from being noticed.