I see a light issue in the near future for my windowsill and have been looking for a good supplemental light source that's cheap, long lasting, and easy to maneuver. The space is about 3 feet long and a foot wide, and I'll need the lights for maybe 6 hours a day. I've played with the idea of just hanging a regular CFL or two and being done with it, but I thought it'd be wise to consult the experts before I made anything. SO... just regular bulbs? Since T5/T8/T12 fixture? What do you guys think?
For supplemental light, there are thousands of potential options.
CFL's might be adequate, but you'd need a good reflector to direct the light to the plants.
For the space you have, a single 2' T5 HO lamp with good reflector would be better. Here's one from Hydrofarm.
I sell a lot of these LED lamps for that purpose, and they're hard to beat from a longevity and operational cost perspective, and generate less heat than the other options.