You don't need a garden (or an allotment) to grow decent vegetables. Crops in pots can be grown up steps, on balconies, in driveways – anywhere, in fact, where a pot will fit and where you can water and feed it without putting on crampons and a harness. You need biggish pots though, otherwise they dry out too quickly and roots run out of space. Look for cheap plastic pots (they don't dry out as fast as terracotta), not less than 35cm across.