HI Newfie and welcome. If you get the highest wattage CFL (Compact Fluorescent Lamp) you will be able to put the light a couple of inches away from your plants. If you try to put regular incandescent bulbs that close, your plants will get cooked and die. If you keep the incandescents up high enough to not cook the plants, they'll stretch upward in an effort to reach the light. The strecthed out stems will be weak and your plants might even not be able to support their own weight. Plus, CFLs will screw right into your clamp lights. Try to get ones that say "Daylight", "Sunshine", "Sunlight". If you can't find those and your choices are cool white or soft white, get cool whites, it's a better color for plants. Hope this helps. :thumbsup: