How many plants? For two or three pots, use one of the screw-in spirals, with a reflector. You can use a Verilux but they are expensive and not necessarily better. For many pots, use four foot T8 fluorescent tubes.

Use a mix of daylight or cool white tubes, with warm white tubes. Or use a Gro-lux type tube but these may be difficult to find and expensive. Any of these are fine for supplemental light. For use as the only light, you might want to use a daylight (5000K-6500K) tube with a CRI near or above 90, to make the colours appear more realistic and vibrant.

Use the lights on a timer. 14 hours light per day will give good flowering. Look out for leaf scorch. Move the lights further away, up to a foot. If they are already a foot away, try a fan, or use less light. You will probably be familiar with the symptoms of too little light, pale spindly stretched growth, poor flowering.

Thanks for the feedback! I have a couple of AV's sitting on my windowsill and wanted to give them more light to keep them blooming. I just added a screw-in spiral with a steel reflector about 12 inches from the two. I don't have enough room for tubes--although I'd LOVE to...If I had my way, I'd have a whole room dedicated to my plants!

By the way, what are "T8" fluorescent tubes? Is that a brand or a type of tube? My past experience with tubes has been to get those "Growlight" pinkish tubes at Kmart...which I'm not sure are that effective. Any thoughts?