Usually the tubers left in the ground rot over the winter.

Read up on how to "cure" the tubers when you harvest them. Once they are properly cured they usually last til planting time the next year.

I usually just plant any tubers left over that sprout as long as its warm enough outside. Don't plant them until summer like, night time temps show up. I don't mess with starting from slips, I just plant any left over tubers whole. It gets them off to a strong start.

i have some sprouting under the sink. you figure it's too late to start them? I think i'll take them to gg where they'll get the best sun.

I'd plant them. They may only produce some small tubers but that's better than nothing.