I built a fenced enclosure and cultivated sweet potatoes (from civilisation) and yams (from the wild) in it. I originally had a small 3X3 m garden behind the wattle and daub hut that already had some sweet potato and yam vines growing in it that were planted after the hut was built. But wallabies kept eating the leaves. So I made a wattle enclosure around it to keep them out. Wood ash was added to the soil to provide potassium and phosphorus for the growing tubers.