As I frequently say, a condo is not the ideal place to do serious gardening.
But, if you are serious (and have a bit of room), you might consider a coldframe or simple greenhouse. A small greenhouse for starting seeds early or carrying plants over the winter can greatly extend your growing season.
David LaFerney has some great ideas for both on his Door Garden site.
Greenhouse from recycled materials
His site is also a good resource for backyard organic gardening.
