Gary Woods writes:
But that's not the question, which is: How long can I expect the 4
carrot-sized tubers I got to keep in a cool dry cellar pantry?

Probably not very long. 1 or 2 weeks. If any has been scratched or cut with
a knife then it is likely to spoil from that point and once started
spoilage spreads quickly. Store-bought sweet pots can store for months, but
they are fully matured and dry and I only store those showing no surface
damage and which have no cuts, none on the stem end and none on the tip end.
Only where the ends have preserved the natural tapers to their tip do they
have potential for lengthy storage; if you can see a cut section of potato
then expect it to soon go mouldy there with time.

The cuttings, which rooted quickly in water and now live in a glass on the
windowsill should really be potted in dirt, no?

Ideally, yes, but they seem to stay healthy growing in water for weeks.
Do you have a sunny window where you could stand them planted in soil?

It's a bit difficult to explain the taste, but I find that whenever a
sweet potato develops even a tiny bit of rot or mold then the whole of
that tuber carries an unpleasant taint, no matter how much I cut off and
discard before cooking. So I advise against storing them until you see
a tiny bit of decay--that's too late to stop the whole thing being spoilt
in taste.

The best way to cook both white and pink sweet potatoes is to wash the
whole tuber clean, dry it and rub all over with olive oil, puncture all
over a dozen times to 1 cm depth with a kitchen fork, then sit it on a
piece of oiled aluminium foil on a shelf in the oven. Cook until it is
nicely browned and collapses on being pressed with a fork.
--
John Savage (my news address is not valid for email)