search for "step by step how to build a bubble bucket" rumpleforskin is the guy who did it, it's a great tutorial and easy to follow.
Rumpleforeskin is definitely THE pro on the matter of DWC. Look for his grow journals in the grow journal section, thoroughly detailed and very, very effective. Basic jist of it is what the other poster said though, You need a bucket with a fitted lid, some airline tubing, some air pumps and stones, a net pot and some hydroponic medium of your choosing. ...To build it. The maintenance can be easier/more difficult depending on your skills. Building it shouldn't be a problem, but you will need extra equipment and know-how to manage it.
I'm currently on my first grow using DWC. I did a "do it yourself" basicly one of these: SH Hydroponics, Inc. > Dual Spectrum Bubbleponicsâ„¢ Complete Kit Something I ran into as a learning experience so far using DWC: - Light leaks in reservoir causing algae - Reservoir temps being to warm causing root rot - Maintaining pH levels But once you get everything down it's easy. Also a link to rumple imfamous bubble bucket here: http://forum.grasscity.com/do-yourself/121335-lets-build-bubble-bucket-step-step.html
