The basic configuration includes three bottles that act as plant holders, a bottom reservoir to capture/hold water, and tubing to move water through the system. It also utilizes a small air pump that uses water displacement to elevate the water up to the top of the system, where it can then trickle down through each plant.
Hydroponics. Looks fun and not very complicated to make. We will let you know after we make one here at seedsnow!!
Don't let limited space deter you from gardening. Thanks to TreeHugger for this great article about Hydroponic gardens!