This way ideal growing conditions can be achieved free from contamination. However an outside exhaust ventilation opening is important, such as a window or door. All openings must be well screened to keep out unwanted insects. Choose a low traffic area that can be made completely dark quite easily. The plants will benefit from having uninterrupted total darkness for some of the time.
Electricity is crucial.
The more power that is available the larger the installation you can consider developing. You'll need a water source nearby, preferably with both hot and cold water so you can mix to the right temperature before adding water to your garden. A floor drain is also useful. Reflective material on walls, floors and ceilings will help to keep the area clean, but more importantly will ensure you get the most out of your lighting. Flat white paint is fine, however a specifically designed reflective material such as mylar is ideal.