On sunny days when I am driving around town, my eyes wander to parking strips, those three-foot wide strips of grass that run between the street and the sidewalk. They are seldom landscaped or otherwise even noticed. Because of rules limiting anything that could block a driver's view as they back out of their driveway, these parking strips are often in full sun. I think the same thing every time I contemplate these parking strips, "Just think how much food could be grown right there!"
There are some neighborhoods around Seattle where you can see examples of parking strip gardens overflowing with zucchini, kale, tomatoes and beans. As long as you don't block visibility for drivers, the city is very tolerant of the space being used for something other than grass.
My brother is an apartment dweller in Oakland, California with a green thumb and has found a few ways to grow food without a yard. He has converted a tiny sidewalk spot into raised beds and has a collection of pots filling his patio and greeting him at the front door. He says that he has had little problem with people helping themselves to the bounty.
He was skeptical of the patch of the litter filled dirt between the stairs and the garage, so he lined the inside of the raised bed and brought in clean soil. Considering Seattle's cold spring, I am a bit envious of his basil.