sweet potato harvest

My first ever attempt at growing sweet potatoes and today was harvest day. I started these sweet potatoes last February by buying two big ones from Whole Foods market, burying them in moist dirt and letting them sprout. Only one of the potatoes sprouted, but it did it vigorously. In May, when the ground was quite warm I stuck the slips in the dirt and proceeded to ignore the patch for the rest of the summer. I had no idea if they were growing anything, except leaves. Plenty leaves were being produced! Our average first frost day has past and the weather has been getting quite cool. Sweet potatoes should be harvested before the first frost so I decided to uncover my buried treasure today. I got 23 lbs out of 16 sq feet of garden. The pictures were taken a minute apart. Before-- leaves After--sweet potatoes