Hmmm. I saw that video years ago. His results/yields are mostly due to the variety that he planted; which is Sarpo Mira. From what I have read, that variety has to be killed (the green tops chopped off) in order to stop the potatoes from growing ever larger.
I got excited too, when I first saw the video. I recall thinking, wow! a true peasants potato and that I needed to grow it to feed all these little kids running around here. Unfortunely, it is not available to us peasants of the USA.
