Store potatoes are supposed to be sprayed with a growth inhibitor to prevent sprouts, but they probably will grow okay since they are started. Many claim that store potatoes are more likely to have diseases. How much of a threat that is for a small garden, I don't know.

I would be more concerned about it being rather late in season, I planted my potatoes in 5b six weeks ago and they are near flowering. Potatoes like cooler temps for the up above ground growth. Potatoes are pretty easy, you may still get something if you plant them.

I don't mind sprouts on a potato but when they sprout AND start to shrivel, they can go right outside and get buried. There will always be more than enough to plant, cut up or not. Note that except for now, we have a very mild climate and can get away with stuff like that. Your mileage will definitely vary.

There's this thing going around about how grocery store potatoes have been sprayed with a seriously toxic sprout inhibitor and they won't work as seed potatoes. That is not a problem if they're sprouting. My father in the last century would plant the sprouted ones left in the bottom of the barrel in the cellar come Spring. He'd cut them all up and rub sulphur on the sides. It all worked.

Try it. There's nothing to lose in any way at all.

I didn't even know about "Bud Nip" but I'd guess not all potatoes are treated with it?

I have grown potatoes for years and have bought seed potatoes just once. The reason mainly for not planting store bought is that they are treated with sprout inhibitors to retard sprouting. But once you see them starting to sprout then it should be fine to plant. Even you can set them in single layer on kitchen counter and watch them and plant the ones that sprout.

Wow....what great responses! I never heard of a "growth inhibitor spray" but that's very interesting. The good news is that these potatoes are most definitely sprouting. Some have 4-6 inch sprouts and probably would have leafed some if I didn't have them in total darkness.
Noki's comment about it being late for planting potatoes is valid and something I am concerned about. However, I am most interested to getting the little baby new potatoes so surely I'll have time for that. Also, last year I didn't get my potatoes out until the end of may and they made it, so hopefully I will be ok this year too! But again, good points and I appreciate your warnings. BTW....after this past brutal winter and the resulting damage to my fruit/fig trees, I gota love a nickname like "cold_is_evil"! ha.

Late or Not?

Potatoes are planted early for 2 reasons:

1) Down south it is planted early so that it is harvested before the scorching July/August heat sets in. Potato will not produce tubers when the soil temperatures stays too high around the clock (~>75f ?).

2) They plant early in northern states because they have a short growing season. Potatoes need 90 to 120 days from planting to harvest (depending on the variety)

So then, if your summer temperature are not too high and you have about 100 days (+/- 10 days) till your first frost date, you can plant potatoes now.

Thanks for the input, seysonn, it was very helpful. I've certainly got more than 100 days before frost, but if tubers won't form in high heat, I may be in trouble after all....anyway, I guess I'll try and see what happens. Thanks for the help.

BTW....all my life in this part of the country (Tennessee) I've been taught that sweet potatoes are one of the later things to be planted, usually around Memorial Day or after. And I have followed that and had outstanding results every year. (There is however, some debate on whether to pick before or immediately after the frost kills the vines). Are sweet potatoes different in terms of being able to form tubers in the heat or have I just been lucky and/or could have done even better with earlier planting (although, sweet potato slips aren't even available here until late may)

Sweet potatoes are different. They need heat, and you definitely want to harvest before frost. They also need long curing at relatively high temperature and humidity.

"Irish" potatoes can tolerate cooler temperatures, poor soil, and are true tubers. You can dig them after the plant flowers as new potatoes (after 1.5 - 2 months), or wait until the foliage dies either naturally or of frost, and then dig as storage potatoes. They are susceptible to late blight and many of the same diseases as tomatoes since they are also in the nightshade family. Sweet potatoes are related to morning glories and have similar vines and flowers.

BTW, you can eat sweet potatoes leaves but Irish potatoes leaves (and the actual fruit, if you get any, look like little green tomatoes) are toxic.

What an amazingly informative post! Thanks for settling the question of when to dig sweet potatoes! I have dug mine before frost most years but many of the "old timers" around here believe that letting the frost kill the vines and then digging up the potatoes the next day somehow makes them keep better over the winter. Most likely an old wives tale it sounds. Also nice to hear about curing....Last year for first time I laid my sweet potatoes out on a wire bakers rack in an 85- 90 degree attic area with a fan on them for almost 2 weeks....they kept INCREDIBLY well all winter long and I still have viable sweet potatoes I dug last October. So I can vouch for your curing statement! Also fascinating to hear that "Irish" (I thought that was just rural-speak for describing Idaho-type potatoes but is what we call them too) potatoes are closely related to tomatoes. As you probably can tell reading this thread, I have far less experience with "irish" potatoes than with sweet potatoes. I love the latter, not only because I prefer to eat them, but I also enjoy watching the vines grow so vigorously. Now I have to go research your last statement...who knew you could eat sweet potato leaves?:) Sorry if this thread has veered to far off from original question, but the subsequent posts have been so interesting I couldn't resist. thanks all.