I'd be anxious to know as well.

I bought about 8 pounds of potato for 31 cents a pound at a local farm store that just got them in.

Last year I bought a five-pound bag for $6 at another store and they also began sprouting. I even put them in a dark box to keep sunlight from them and in a cold area, but they still sprouted.

This year I am leaving them in the bag and put them in an area about 55 degrees and fully dark (kind of like a root cellar) so I'll see how these turn out.

Here is a link that might be useful: BsnTech Gardening Blog

It's the warmth of where you are storing the 'taters that's causing them to sprout. Try to get them cooled off. I'm not a potato expert, but I wouldn't do anything to them except cool them off.

I have some sprouted potatoes that I will be planting soon. Temps in the west are rather warmer than normal and potatoes can be planted when the soil can be worked. I'll be mulching them heavily with straw to protect them from freezing, but they do recover from getting frostbite. The cool soil should stop their growth.

Like Idaho said,
you can slow the progression by dark and cool,but then after that,pre-sprouting is fantastic,you know all those sprouts are going to produce killer taters, you are blessed, I am already planting (10 so far) but am waiting for the rest to sprout ,so I can be assured of a great harvest....tick tock, tick tock ;-)... pre sprouting is the best way to go for the backyard potato grower ;-)
So many people who plant unsprouted potatoes and don't get a good harvest is because they don't even know if their seeds are sprouting... it is best to see tons of sprouts and be careful planting them (sprouts up) and you will see an awesome harvest...

Here is a link that might be useful: Last Years Potato Harvest 2009

adamark,

Double brown bag them, stick them in the frig, in a spot that does not freeze. In 2 or 3 weeks, if temps, soil is right, warm them up and plant. Good luck!

David

How big/long are the sprouts? If they are just starting,
thats ok. But you have to plant them like 6 weekd before your last frost date.
Say, you last frost date is May 15, then you can plant them April first. If sprouts are just beginning, you are in business. Just keep them single layered in a cool place with some light.