When do we harvest the tubers?

A properly adapted oca would die back after tuberising, just as potatoes do. We’re not there yet, so have to make do with the next best option: harvest the tubers after the plants have been frosted off. If there are no frosts until late, so much the better – the plant will continue to shunt sugars from leaves and stems down to the tubers, swelling them. Leave them a week or two after a killing frost before lifting as this process continues for a while after the tops have been zapped. Watch out for rodents and take action. They can and will destroy entire crops.