This summer I decided to plant more sweet potatoes; I'd gotten a handful of slips for a song at Marshall Grain before they closed the Lancaster Street store, and they sat in a cup of water until I had the keyhole-shaped raised bed ready. I've never had much luck planting them for the tubers, I was putting them in for the lovely vines. Beauregard variety (what you find in the grocery store most often).
Months passed and my next door neighbor and I were quickly harvesting everything before the first frost. I commented that I ought to look to see if there was anything to dig up since the vines were everywhere, wrapping around eggplant, poblanos, curled around and climbing the okra. Sprawled across many square feet of lawn, climbing the volunteer wild sunflowers, tangled in the cherry tomatoes. What we found was astonishing - sweet potatoes the size of footballs, so deep and so large it was difficult to dig them out. We got a few, then left the rest for another day; underground the tubers were protected from the freeze. These are a few that I dug the first day, in a large stock pot (for scale):
Again, for scale, my garden shoe is a size 9 women's sneaker.
Every so often I would go dig a few more. They were corkscrewed into the soil, wrapped around each other, so large that it was like an archaeological dig to keep the large yet brittle potatoes from breaking off if we tugged on part of one still buried.
My daughter loves to come help with the harvest, and on the warm Thanksgiving (2016) afternoon, she spent time in that same bed still digging potatoes.
I went out some time later and thought I finished digging out the bed, but then I pulled the vines up off of the lawn and several potatoes popped out of the ground as I yanked on the vines. So I dug around in the turf and found another ten pounds of potatoes.
Today (January 24, 2017) I dug around in that keyhole shaped bed to put in the start of Irish potatoes for this year - and I stumbled upon several more sweet potatoes that I'd missed, deep under where the okra had stood all summer. Four more pounds of potatoes that look in great shape were harvested this afternoon. I hesitate to say this is finished - there are probably a more under the turf still, the messy area where the garden ended and the lawn began and the vines ran rampant all summer. I'll probably find out in the spring, if I find shoots from the still-buried potatoes. (Which I'll transplant into a regular garden bed.)