Lighting is the key factor to growing Marijuana. Without light the plants will die. Find your local hydroponics store and travel there. Upon arrival you should already know how big your growspace is in square feet. A good light measurement for light would be 30-50 watts per square foot. The more the better. You can choose from one of two different types of light. Metal Halide (MH) or High Pressure Sodium (HPS). Metal Halide has a good spectrum for growing and causes the plant to have short internodes between leaves. HPS has a more orange spectrum and also performs well showing better results in the harvest stage . It's really a matter of personal preference of marijuana seeds. My lights are convertible from both MH to HPS. Metal Halide for the vegetative stage and High Pressure Sodium for flowering. While you're at the hydroponics store buy some spare bulbs and a timer. (digital is best)