All you need is a small amount of vertical space around a balcony or an open window which can hang or store a vertical array of drink bottles that can grow all your herbs and lettuce easily. Recycle as many of your plastic drink containers.
you could add some fish to your water reclamation tank for a small aquaponics system. Grow a few plants to feed the fish and this forms a closed system. There is no need to fertilize, the fish do it for you! Permaculture at its finest!