psychocat is correct about having separate veg and bud chambers. Of course you get to harvest twice as often this way. Search sog and scrog if interested.

And ProGrow is correct in that I do have DWC experience. I recommend starting like I did, with an Emily's Garden set-up. Run that through a search engine to learn more, but it doesn't take up much room vertically, it's extremely simple, and it produces fantastic results. It didn't take long before I built a couple of them, since they are so simple, which anyone can do with limited craftsmanship skills. The net pots are a little taller than normal, but they sit directly on the bottom of the reservoir. I recommend altering it, by substituting a bigger air pump and by adding 4-6 small air stones. The bad part about this is doing that will take up a little more room, since you have to find a place for your new bigger pump. The small pump that comes with it tucks neatly under and inside the reservoir. You will still get great results without alteration. I also put some extra holes in the pots near the bottom, since I didn't quite think there were enough.