Small space gardening teaches you that you don't need a lot of space to grow your own food. There are techniques like vertical gardening, sack gardening, rooftop gardening and hydroponic gardening that utilize space well. Urban gardening helps you make the best use of space while growing all the food that you want.
Kampala and Nairobi taught us the ingenuity of growing food in sacks and how to maximize scarce resources like land by growing vertically. Tiny gardening is perfect for when there is not much growing space available or the ground is contaminated. Plants will grow in any direction toward the sun, so planting food all around the sides and top of the sacks is a great way to densely grow a lot of food in a small growing space. All that is needed is some soil, sacks which are usually free or quite inexpensive from the local coffee roasters, compost, seeds and seedlings. For urban food growing, we like to use worm (or vermicompting) compost which is a great way to create high quality nutrients for soil without needing much space and without creating an odor.