I've seen sweet potatoes grow tubers in the space between containers and
concrete patio... very little soil, soil wasn't half as thick as the tubers. The space was wet and dark and the vines had sunlight, that's it. I am wondering if SP needs water & light and a dark place to put tubers more than anything else. Sure doesn't seem to need much fertility.
I have a big trash bag full of oak leaves I picked up off the curb. Maybe I'll water it and stick SP slips in it like a pin-cusion and grow a bag of SP's. ?
Yesterday I took some plastic
milk crates, lined them with
cardboard, filled them with soil and partly composted woodchips, poked holes in the cardboard sides and stuck SP slips in. Soaked the whole thing. A variation on the potato tower idea. We'll see if I get any yield.