I dug the first sweet potatoes, Korean Purple, with baited breath. I tried digging around with my hands in the soil before and could find nothing. I always thought they grew toward the top of the soil. But mine liked it farther down. The ones on the edges grew toward the outside trying to get into the hard packed dirt that forms the base of the brick path. They didn't succeed mind you, but I'm guessing they were growing toward the heat. Those were the hardest ones to dig out. Purple was a strange one. It sent long thin potatoes out into the white sweet potato row. Those were very crooked and long.
I suppose I ought to say something about curing squash and sweet potatoes. Neither of these are eaten right from the garden (though you can cure squash in the field). Both have to be cured because it allows their skins to toughen up and any wounds to heal. It also converts starches to sugars. Sweet potatoes aren't so sweet straight from the ground, but the longer they are stored, the sweeter they get. Both are cured for about two weeks at 80-85F. Though you can do it at lower temps if you cure them for a longer time. Since I've yet to cure a sweet potato, I'm trying to give them fairly good conditions to see how long they will store here.