I had heard that you can increase the number of potatoes from a single potato plant by starting with a box and as the plant grows add another layer of dirt in the box till it's a couple feet tall, then just open a side and let the plant fall out of the column and voila! more potatoes. I've never tried it, has anyone else? and would it work for sweet potatoes?
I saw an article like that. Seemed to work. Give it a try, and let us know! Sweet potatoes, too.
Good luck, and I might give it a go myself! Need to get 4 pieces of ?? plywood. It's all treated here. I don't want to garden in poison, and what they treat plywood and lumber with is really bad stuff.