Should I Run a Dehumidifier in My Grow Room?

Monitoring

• Since the grow room is designed to retain all of the heat and moisture used in a plant-growing operation, the room tends to become overly hot and humid. This may cause the plants to have trouble with respiration and could ultimately lead to problems with mold, mildew, disease and possibly even the death of the plants. Monitoring the room on a continual basis helps determine if the growing conditions need any modifications, such as a reduction in humidity. An inexpensive weather station placed in the room with a readout display outside of the room can provide ongoing information about growing conditions.

Exhaust

• It is important to move all of the old, stale, humid air out of the room on a regular basis. This helps keep conditions inside the room from becoming too hot or humid for the plants inside. The best situation is if the room’s exhaust opening is located at or near the ceiling. This takes the hottest air out of the room and keeps the plants from becoming overheated, a common problem because of the lights that are used in a grow room.

Air Intake

• If fresh air is not brought into the grow room, the air inside may become stagnant and overly humid. The exhaust removes the old air, and the air intake should be set up to bring in air from outside the grow room. In most cases the intake brings in air from other parts of the home or from immediately outside. The fresh air helps keep the humidity level down, especially when combined with the exhaust.

Humidity Levels

• The humidity levels in the grow room should be continually monitored to make sure the air doesn’t become overly humid. A desirable level is between 40 and 60 percent, as shown on the weather station readout. If the humidity gets too high, the best way to handle it is to increase the speed and power of the air exhaust and intake fans. If the level continues to be too high, it is possible that running a dehumidifier is the best solution for the situation since levels over 60 percent will interfere with the growth of the plants.