I can almost categorically state that oca can stand 7 degrees frost, but not - 8 Celsius. We recently had a long cold spell and I had not dug my oca. Almost all the tubers had turned to mush other than a very few that seemed to be protected a bit by the
shelter of a pallet
fence. Note to self: harvest before xmas even if it
is wet out.....
I'm a bit sad because I had been looking forwards to assessing the yeild on different colour tubers I got in 2019. Still I have a few to play with this year.