Have you thought of getting Earth Boxes? They are a sort of semi-hydroponic system, the boxes are made of recycled plastic, and come with casters and they are extremely water-efficient. (you're going to have to consider the water from your plants dripping down onto your downstairs neighbors, right?) I can grow 3 or 4 tomato plants or 4 broccoli plants in each one. Once you get them properly set up according to the directions, all you have to do to grow awesome plants is make sure you keep their water reservoirs full and keep them in the sun.