A grow room is a popular home feature for gardeners who want to grow plants indoors without the use of a greenhouse. While some homes come with sun rooms for growing plants, a grow room typically has no windows. The advantages of such a feature are that the gardener can precisely control the amount of light that the plants are exposed to.
Since grow rooms have no natural light, all light must be supplied artificially by specially constructed electric lights that simulate the lighting color temperatures given off by the sun. Most grow lights are placed in a lighting hood so that all light from the bulbs is directed downward at the plant. Grow lights may be LEDs, incandescent lamps, high intensity discharge lights or fluorescent lamps. These lights are usually placed on a timer so that the plants receive an optimal amount of light.
In most all indoor plant systems including grow rooms, grow boxes and greenhouses, ventilation is an essential component. Plants can only thrive when kept within a certain minimum and maximum temperature range. In a grow room, the heating system controlled by the rest of the building prevents the temperatures from dipping into ranges that are too cold for the plants to survive, but a grow room requires a ventilation system to remove heat from the grow room. This is especially important because the lights that substitute for sunlight for the plants also produce an inordinate amount of heat. Some form of ventilation includes exhaust and circulation fans and vents, air-cooled lighting reflectors and even small air conditioners.
Because many of the grow rooms today are sealed against light and insulated for temperature changes, they require internal air filters. Just as humans can become sick when exposed to old, breathed air, plants can grow poorly when grown in stale greenhouse air. Air filters help to recycle the air by pulling it through carbon filters filled with activated charcoal. These filters remove impurities from the air, including spores, dust and mildew that can harm a plant before returning the air to the grow room.