If you don't have the space, but the residents have patios, or you have common areas that could use a little flower power, Urban Garden offers a pocket garden system made from recycled bottles for $29.99! It makes a perfect move in gift for the gardener, and imagine how these could beautify common area spaces! If your budget is tight, there's a 2-pocket flower box for $15.99. Both are lightweight and fold for easy storage.
For that ugly old wall you just don't know what to do with, Plants On Walls living wall kit will allow you to create gardens where you never thought possible. A 32' by 51' wall kit starts at $528, and can be rearranged as the mood fits.

So, there you go - get your gardening gloves on and get busy.
Anybody doing interesting things with you community gardening efforts? Don't hesitate to share.