How Hot Is Too Hot for a Grow Room?

Monitoring

• To keep an eye on grow room temperatures, it should be monitored on regularly. The best way to do this is to install a weather station in the room, not too close to the light. Place a readout station in a convenient location outside the room that will provide continual reporting without the need to enter the growing area.

Causes of Heat

• A grow room gets too hot for two main reasons. The first of these is the presence of a lighting system in the room. A grow light can raise the temperature of a room significantly. How much depends on the size of the room, the size of the light, the temperature outside the room and how many hours per day the light is on. The other cause of a hot grow room is lack of adequate air circulation. Stagnant air will heat up and increase the overall temperature of the room.

Considerations

• One factor that affects how hot a grow room should be is what kind of plants are being grown there. Some types of plants prefer cool weather. For these plants, such as spinach, lettuce and other cool-season crops, the preferred maximum temperature for the grow room is about 70 degrees Fahrenheit, though it can go as low as 50 F at night. Warm-weather plants, including eggplant, peppers and tomatoes, do well with considerably higher temperatures, up to 85 degrees F in the day and about 70 F at night. All plants can tolerate higher temperatures for a short time, though their growth will slow and the plants will begin to wilt.

Temperature Control

• Several things can be done to keep grow room temperatures within the required range. The light should be appropriate for the room size so that it doesn't overpower the space. Outside windows should be blocked off to prevent extra heat from entering from outside. Ventilation must be set up that brings in fresh air from outside the room and exhausts the hot, stale air from within. This is extremely important for a grow room and is necessary to control the room temperature.