"Eight months in a major barrel and this is all I got..... all very deep and right under the plant, by the way. But lots of unproductive roots thru out. These cook up bright translucent yellow and are quite sweet. Waste of time for a container situation, far as I could see. Could have grown almost three generations of Peruvians for ten times the yield in that same amount of time, and space. Plants make effective and attractive ground cover, however. "
I don't have any experience using containers for sweets, so I don't know if this would be an expected result.....undersized tubers, long growth period. I'm sure there are climatic factors going on here, but also variety factors too.
Growers often say how the non-commercial varieties of sweets are fickle. Some years they produce, some years nary a tuber. Some parts of a field will be great, other spots in the same field...nada. That's one of the reasons commercial varieties were developed. There was a need for consistent production. A field that didn't produce after all the time, effort, and expense put into it was a major hurt to a farmer trying to make a living.
So why grow non-commercial sweets? They often taste way, way better. And there's lots of variations that fit the various nooks people deal with. Some withstand heat and dry, some do good with moist and humid conditions. Some can take a chill, others no. Some taste too sweet for some folks, and others are barely sweet at all. Some produce in rocky or sandy soil, others do fine in compost. Some produce tubers under the mother plant, others spread tubers all around. Some make only a couple giant tubers, others abundant small ones. Some are only good bakers while others are only good fryers. So there's sweets to fit just about every gardeners' situation and desire. But they can be challenging at times.
I've not even come close to figuring out sweet potatoes. It's always a miracle that I find tubers when I dig them up.