I had it at too close, in the beginning, so they never reached for the light, and so I now have a plant the size of a large box turtle, you can tell I finally figured this out, because the younger batch of plants are going to be way bigger. How close did I have my light? I got 400 hps, plants were month old my light was 12 to 13inches above them. I kept it cool so light never burned em, just a lil stress. Well I realize now it should have been more like 18inches, and they would have reached up too it. I'm stoned and rattling on.