My elder daughter lives in a unit in western Sydney which has a large and a small balcony area. We did up a permaculture plan for the larger balcony but I left the smaller one out because it is really small and only gets light at certain times of the day. A while back I gave her some recycled containers that I got from a friend and she has gone full steam ahead and used them to create a herb garden on the smaller balcony.
The containers are white plastic ten litre ice cream containers, my friend runs a nursing home and they use this ice cream on a regular basis. If nobody has a use for them they are thrown out so I got hold of nine and kept three for myself (they are great for storing compostable materials before I toss them in the composter).
To create the herb garden all she did was drill a couple of 5mm drainage holes in the front, bottom of each container, then drill two holes in the back of each container near the top. Through these holes she threaded some thin rope and tied the buckets to the rail. The rope is sized so that back bottom of the containers are balanced on the edge of the bricks which make up the wall at the edge of the balcony and on which the steel handrail is mounted. This creates a tilting effect so that the water runs forward to drain holes and supports the containers so that most of the weight is taken on the bricks rather than on the rope.
She filled each of the pots with a good quality potting mix and then planted each of the six pots with a different herb – sage, parsley, chives, thyme, basil and mint. With everything in place she has a space that is newly productive, herbs to use whenever she wants and it has been accomplished by reusing containers which would have been thrown out!