Long story short... I planted a patch of sweet potatoes last year but moved (I still own the property), so I never had a chance to dig them up.

Will they grow new potatoes this year from the old potatoes, and will I have any kind of problem with a bunch of rotten potatoes from the year before or will the break down by next harvest time?

One more question i guess (I have never grown sweet potatoes before) are they already ruined if I were to try to harvest them now, they have been in the ground all winter.

Sorry for the noobie questions :(