You don't need much space to grow a lot of food!!! This video shows a 2000 square meters garden in Belgium with several thousand of fruit trees, bushes, and veggies gardens... Thanks permaculture!
If you want to learn more about growing your food, permaculture and so on, come to the raw fruit festival in Spain, 12-16 September 2012! You'll get the chance to talk with some experienced permaculture growers and visit their farms.