Beans: A great choice because they are tasty fresh or frozen, and there so are many varieties available. Do some research, though, because you may require a trellis…
Blackberries: They can grow almost anywhere you have the space and they are very low maintenance. When picking, beware of the thorns, wear thick gloves or try a thornless variety.
Carrots: They are easy to plant from seed, and you know they are ready to pick when the tops are visible above the soil. They tend to be a hit with kids, too.