The nice thing about grow lights is that the plants grow straight up and more compact in than in a window. When I first started gardening I started everything in my window sills. The more cloudy days you have the skinnier and longer the stems of your plant will be. Of course, Windows aren't the only thing that can cause that problem. It's tempting to get ahead of myself sometimes and move the lights up when the plants are getting closer to the grow lights. But if I move the front row of lights up too soon, the plant will more than likely become "leggy". The plant will stay more compact if I leave the lights close for now. This will help the plant to not grow tall and spindly. A weak leggy plant is more easily damaged by wind when I transplant it outside. Of course it is not as bad with tomatoes. I bury most of my tomato plants in an eastward trench filled with egg shells so that only a small portion is visible. The eggshells prevent blossom end rot by providing much needed calcium to my tomatoes (I have the most nutrient lacking clay known to mankind in my yard). Keep the lights close. I've never had burn issues with my plants touching the bulbs.