Cannabis humidity
Cannabis & Humidity – What Is the Ideal Level?
Humidity plays a more significant role in cannabis cultivation than many realize. If the levels are not right, growth can stagnate—or worse: mold, nutrient issues, or stressed plants often result. For this reason, it is important to pay close attention to humidity, adjusting it according to each growth phase.
Why Humidity Matters
During the vegetative stage, cannabis plants require higher humidity—ideally 60 to 70 %. This allows them to absorb additional water through their leaves, reducing the burden on their young roots. Too dry means stressed leaves. Too humid increases the risk of mold. The key is to maintain the right balance.
And After Harvest?
Now it’s time to dry—but do so slowly! To preserve both flavor and effects, humidity during drying should be maintained at 45 to 55 %. If it is too humid, mold can develop. If it is too dry, the cannabis loses aroma and quickly becomes harsh. The principle: slow, controlled, and even drying.
What Humidity for Each Stage?
- Seedlings: 70–80 %
- Vegetative stage: 60–70 %
- Flowering stage: 40–50 %
- Drying: 45–55 %
By following these values, you create the optimal environment for each phase and maximize the potential of your grow.
Temperature & Humidity – The Importance of Their Interaction
Temperature affects how comfortable your plants are and how much moisture they require. During the day, 20 to 30 °C is suitable, while cooler temperatures are acceptable at night. During the flowering stage, conditions should be drier and cooler overall. This not only helps prevent mold but also promotes resin production.
Especially Important: The Flowering Stage
This is the critical phase: During flowering, the final appearance and effects of your product are determined. The target humidity here is 40 to 50 %; anything above this can cause problems. Lower values also encourage trichome development, which directly enhances potency and flavor.
What to Do If Humidity Is Too High?
- Dehumidifiers: The simplest and most effective solution
- Fans: Ensure air circulation and reduce moisture pockets
- Adjust watering: Prefer smaller amounts more frequently rather than too much at once
With these basics, you can maintain a stable climate in your grow room—regardless of the season.
The Seedling Stage – Sensitive but Crucial
Seedlings require high humidity of 70 to 80 % because, at first, they can barely absorb water through their roots. If conditions are too dry
they dry out—before they even have a chance to start growing properly. A small dome, a heated mat, and regular ventilation are helpful during this sensitive phase.FAQs
Why is humidity so important when cultivating cannabis?
Because it directly affects growth, plant health, and ultimately the quality of your harvest. Too humid? Mold. Too dry? Growth stops. Humidity levels must be appropriate for each stage of cultivation.
How do I measure humidity in the grow room?
The best way is to use a digital hygrometer. It displays current readings and often also min/max values. It is important to place it at plant height—this is where the climate matters most for your plants.
What can I do if it is too humid?
Use a dehumidifier, open windows regularly (for outdoor cultivation), set up fans, and water less if necessary. Increasing the distance between plants can also help prevent moisture buildup.
How does humidity affect the harvest?
The drying phase is especially sensitive—if it is too humid, Flowers can develop mold. If it is too dry, they become brittle. Only with the right humidity are aroma, potency, and consistency preserved.
Do I need to regulate humidity differently at night?
Yes, at night the temperature drops, which increases relative humidity. Make sure it does not exceed 70%—otherwise, there is a risk of mold. An automatic dehumidifier with a hygrostat is extremely valuable here.