How to Raise Humidity During Drying: 5 Methods for Cannabis

The top pick for raising humidity during drying is a cool-mist ultrasonic humidifier paired with a hygrometer controller. That pair holds a steady 45 to 55 percent relative humidity without soaking the buds. I ranked each method on four criteria: control accuracy, mold risk, cleaning effort, and impact on drying time.

Cannabis Dry and Cure Humidity Chart: Target RH by Stage

Method 1: Cool-Mist Humidifier with a Hygrometer Controller

This is the top pick because it lets you set a target humidity and walk away. The controller switches the humidifier on and off as needed.

will low humidity ruin drying weed

Pros: precise control; works in a sealed tent or closet; handles large batches; easy to adjust for different stages.
Cons: needs distilled water to avoid white dust; requires weekly cleaning; a faulty controller can overshoot.

Use case: best for drying four ounces or more in a grow tent, closet, or small room.

will low humidity ruin drying weed

Method 2: Wet Towels or Sponges in an Open Bucket

A wet towel hung over a bucket adds moisture through evaporation. It is a low-cost option when you do not have a humidifier.

Pros: no electricity; uses items you already own; raises humidity in a small space.
Cons: hard to control; can spike humidity above 60 percent; towels can grow mold if left for days.

Use case: best for a small batch in a closet when you need a short boost for a few hours.

Method 3: Damp Newspaper or Cardboard on the Floor

Laying damp newspaper on the floor increases surface area for evaporation. This is a crude fix that can work in a pinch.

Pros: cheap; no special gear; quick to set up.
Cons: messy; ink and dust can stick to buds; can raise humidity too fast; fire risk near heaters.

Use case: best for an emergency only, and never in the same room as open cannabis flowers.

Method 4: Evaporative Wick Humidifier

An evaporative humidifier uses a fan to blow air through a wet wick. It adds moisture without white dust.

Pros: no white dust; self-regulating as wick dries; good for larger rooms.
Cons: slower than ultrasonic; wicks need replacement; less precise for small tents.

Use case: best for a full room where white dust would coat buds and equipment.

Method 5: Bowl of Water with a Fan

A bowl of water placed in front of a fan increases evaporation. This is the weakest method on the list.

Pros: free; uses common items; no cleaning beyond the bowl.
Cons: little control; the fan can dry buds too fast; humidity may not reach the target.

Use case: best for a tiny batch in a large room when no other option is available.

Target Humidity and Airflow

For cannabis drying, aim for 45 to 55 percent relative humidity and 60 to 70 degrees Fahrenheit. Keep indirect airflow moving around the buds, not blowing on them. A sealed room holds humidity better than an open space. Check the hygrometer twice a day. If humidity climbs above 60 percent, increase exhaust or add a dehumidifier. If it drops below 45 percent, run your chosen method for short bursts. The CDC notes that indoor humidity above 50 percent supports mold growth, so stay near the low end of the cannabis range. The EPA recommends 30 to 50 percent for general indoor spaces. ASHRAE psychrometric data shows that heating air lowers relative humidity, so avoid space heaters in the drying room.