I just harvested my grow (ebb&flow, coco/hydroton, GH nutes, 400watt hps) and saw that the stems are all hollow. I don't remember seeing this in any of my soil grows, but then again, I don't remember much these days anyway . Anyway, I was wondering if anyone else has seen this. I wonder if it has to do with the hydroponics. I'm re-vegging and it is going to be interesting to see what becomes of these hollow stems. Every one is hollow. All the side-branches as well as the main trunk. All hollow.