As suggested by the Provident Living Website, "You can plant in almost any kind of container. Try using plastic jugs, garbage cans, milk cartons, cans, plastic bags, baskets, a wagon bed, kitchen canisters, or clay pots. The bottom of the container should have several small drain holes and be lined with 2 to 3 inches of small gravel before you put in the topsoil. Hang containers from windows, put them on windowsills or in window wells; line your sidewalk or driveway with them, or hang them from your ceiling."
There are an abundance of resources on container gardening. Try some of the following:
Vegetable Gardening in Containers, Texas A&M University
Guide to Container Gardening
Vegetable Gardening in Containers, Virginia Polytechnic Institute and State University
You can even grow plants upside down on grow poles.
There are even places to grow a garden in the center of large cities. On a recent trip to New York, we looked out our hotel window into a rooftop garden. Here is an article on one in Vancouver.
"A garden is never so good as it will be next year."-- Thomas Cooper