Indoor space can be used for gardening too if there's a sunny spot on a windowsill or in a room: container vegetables, herbs, and small fruit trees are all possibilities here. The more vexing question is how to use shadier spaces such as extra rooms, closets and cabinets, garages, storage areas, unused bathtubs, and kitchen counters. Perhaps you never thought of these as growing areas, but where there's space, there's growing potential! I have a very vertical sprouting operation on top of my refrigerator that produces 2 to 3 pounds of sprouts per week for eating and wheatgrass for juicing. You could also raise gourmet mushrooms or brew ginger beer, wine, or kefir in that space. Start a worm bin on a balcony or in a garage for composting organic wastes or for fishing bait sales. There are many possibilities for using even shady urban spaces in a productive way.