by Jorge Cervantes
Air Temperature and Humidity
Use the vent fan, heater, and air conditioner to maintain the proper temeperature and humidity in the grow room. If the grow room contains a heat and air conditioning vent, use it to supply extra heat or cold air, and to aid air circulation.
Keep the temperature about 75F during the day and 60-70F at night in both vegetative and flowering rooms. This is a basic guideline A couple of degrees warmer is OK.
Keep the humidity about 60 percent day and night in the vegetative room. Keep the humidity about 50 percent day and night in the flowering room.
Install a thermostat and /or a humidistat and attach to the vent fan to automatically turn the vent fan on and off to help control temperature.
Install a maximum / minimum thermometer and hygrometer in all grow rooms. For the most accurate temperature readings, install a thermometer near the ceiling, another at the canopy level of plants, and another near the floor. Take temperature readings before lights go on, once in the heat of the day, and 30 minutes after lights go out. Record the temperature and humidity each time and make sure to keep them at the proper levels.