Old folks say Valentine's day, I've seen the frost burn the plants to the ground but they always came back. I can't grow them for what they cost in the store.
I plant em in mid to late Feb, got frost bit last year but they come back before I replanted. Cant beat fresh new potatoes. I usually use a 6=12=12 fertilizer and maybe some muriate of potash.
Feb 15 was my target date... I planted Yukon Gold gold and new potatoes each year... Each time we would get below freezing temps I'd just pile on the hay to protect the foliage. It worked for me.
I always try and plant them around valentines day. I dig a furrow, throw in a good dusting of 10-10-10 or 5-10-15 fertilizer, cover the fertilizer with some dirt, then space the potatoes out about 15" or so, and cover them up. I buy a bag of seed potatoes from our local feed and seed store and cut them up so each piece has a couple of eyes in it. I am no professional, but this method has worked for me for years.