I remember my uncle telling me the tale of my grandfather, Arthur Jenkins, when he started his 'Welsh produce' (grocery) business during the depression, he used to grow his own vegetables to sell in the shop, and used a vacant plot next to the house to grow potatoes. all he did was lift a clod of turf up, pop a potato in the hole, then return the clod, grass side down into the hole then stamp on it. he did nothing then until it was time to harvest them (maybe he was also a pioneer of 'no dig' gardening!!
) he grew enough to turn a profit and then went on trading from the front room until he bought Waterloo shop on the village square in 1945.
My mother's father taught me to garden and always told me to earth up the potatoes, but not once did he say it was because the tubers grew on the stalks, but rather as a protection against frost, first to cover the delicate leaves but later, because the haulms were now raised above the surface of the garden the later frosts would settle into the lower area between the ridges and not damage the leaves.