These are good ways to get seeds for your Tower Garden aeroponic vertical growing system.
The Rain Tower Vertical Hydroponic System /* I'd love to do this as an intro to indoor hydroponics in 2014 or 2015. Grows up to 12 heads of lettuce or other small plants. */
The Tower Garden is a vertical aeroponic food production system designed for urban farms, rooftop gardens, and commercial growing operations. Because of its vertical design, the system is space and energy efficient. The basic unit has a 2.5' x 2.5' footprint, and uses modular stackable growing pots. With an 11-pot maximum configuration, you can grow up to 44 plants per tower,
Build a worm tower: PVC pipe with lots of holes drilled into it. Bury into the ground. Add worms. Add kitchen food scraps. Worms move through the tower and move natural fertilizer with them.