No sweet potatoes?? What happened?Did you know that the leaves of sweet potatoes are edible? It's in the morning glory family, not related to potatoes. I tried to grow them one year and ate a couple of the leaves. Bleah. Tough and fuzzy is how I'd describe them. Maybe they'd be ok cooked, but I didn't try it. Didn't get any sweet potatoes, either, so that was a one time experiment.
I do the same, I let the plants totally die before I did the potatoes. I mark where the plant was with a stake so I know where to dig. I usually leave them in the ground until they start talking about frost. I have enough to do at that time of year, so mother nature can store the taters for me for a couple weeks.
But, your climate is totally different, so this might be no help at all...