Grow rooms are a great way to set up larger scale indoor plant production to supply fresh vegetables in the winter when it is too cold to grow outside. Grow rooms can also be arranged to grow exotic plants and flowers like tropical orchids and houseplants. There are limitless ways to arrange a grow room and a wide variety of equipment and brands available. But most grow rooms have the same basic elements.
Light is the single most important thing you need for a grow room. Without light, the plants will not grow. Common types are metal halide lights for vegetative growth cycles, high-pressure sodium for reproductive growth cycles and compact fluorescent for smaller areas and places where too much heat is an issue. Very low light-loving plants may be satisfied with regular fluorescent tubes.
Fans help move the air around a growing area. Stagnant air leads to uneven temperatures and humidity levels creating micro climates within the grow room inhibiting water evaporation. This can lead to fungal and bacterial infections. Fans also are used to connect with duct work to vent heat from grow lights or to exchange the indoor air with outdoor air.
A water source can be as simple as a small container or watering can to hold water for a small grow room, or a spigot to hook up a hose in larger areas. For large areas, it is better to have a spigot so toting heavy buckets of water is kept to a minimum.
Thermometers and hygrometers are often components of the same device. A high quality greenhouse thermometer and hygrometer will have a setting that records the minimum and maximum temperature and relative humidity level for the set period of time. This comes in handy when growing plants that need a day to night temperature fluctuation to promote flowering or require a constant humidity level.
A timer can save a lot of headaches for plants that require a regular day and night period in order to properly set flowers. It is very easy to forget to turn lights on and off at the very same time every day. Many plants require a slow change in day length that mimics the changing seasons to promote flowering and fruiting. High quality timers can be set to do this.
Lining the walls of the grow room with reflective material redirects the light that misses the plants back toward them, making the lighting more efficient. Some of the most effective and commonly used material is reflective Mylar, or simply painting the walls with a flat white paint.