This was taken from the General Electric site concenring differnet lighting methods. It's a good start at becoming more familar with lighting requirments. I imagine if you had enough room you could equal or better sunshine. Compact fluorescent lamps are more energy efficient than a standard 60-watt incandescent because they use less energy to provide the same amount of light. Fluorescent lamps use discharge technology, which uses energy to create an arc of excited mercury vapor across the lamp. Less energy is needed to maintain this arc than to keep an incandescent filament burning. To provide less energy to the lamp, the lamp is designed to operate on high frequency electronics that reduce the current (energy) used by the lamp. There is no one best fluorescent lamp for growing plants. According to the 9th Edition of "The IESNA Lighting Handbook", lamps that emit proper amounts of energy between 300 and 800 nm provide the proper energy for photosynthesis and other plant photoresponses. Lamp selection is one of personal preference and you'll find indoor gardeners use fluorescent, incandescent, metal halide, and high-pressure sodium type lamps. In general, vegetative plants, such as herbs, will thrive under a combination of lighting that tends more toward the blue end of the spectrum. Flowering and fruit-bearing plants tend to need more light in the red portion of the spectrum. Plants grow under GE's F40PL/AQ plant and aquarium wide spectrum lamps, which offer a balanced color spectrum, including peaks in the red and blue range. This is advantageous, as you would get a balanced spectrum with one lamp instead of two. If you are concerned with the appearance of your plants as well as growth, it may be helpful to consider lamps with improved color spectra and color rendering such as GE's SP (good) or SPX (better) phosphors. Try red-enhanced SP30 or SP0 for flowering and fruiting plants or blue-enhanced SP50 or SPX50 for vegetative plants. Some gardeners also use standard 4-foot cool white (GE F40CW), warm white (GE F40WW), or daylight (F40D) fluorescent lamps. Popular with many gardeners is the combination of a cool white and a warm white lamp.