j42o, if short plants are what a grower wants, then by all means, keep the lights close to the plants. But in doing that you risk some heat damage, especially if it's a 1000W bulb. It's probably true that you ultimately get more product if you grow short, bushy plants indoors, however, a grower should make use of the verticle space too. Ideally you grow plants that are tall but not taller than the lights and fat but not fatter than the room can handle. When you can do that, then you know you've done it right.