Potatoes. They require the least maintenance and if you employ a small greenhouse (really, just a meter high, sticks and plastic sheets as cover) they can be gr

Potatoes. They require the least maintenance and if you employ a small greenhouse (really, just a meter high, sticks and plastic sheets as cover) they can be grown all year round, yielding as much as 4 or even 5 harvests, depending on the potato type.