Sprouting Sweet Potatoes

So I have decided to try my luck at starting my own sweet potatoes this year.  Last year I bought a plant already started and got a few good sized sweet potatoes but the plant was a bit expensive.  I have been getting a veggie bag from local farmers (Loft Organics) the last few weeks and have gotten some rather tasty sweet potatoes so I thought I would try to sprout one of them.  I found this website that shows you step by step on how to go about sprouting sweet potatoes and I have completed Step 1 (except I forgot to wash my potato, I don't think it matters).  Now I wait. 

I never figured you could sprout sweet potatoes as they always seem to go bad in the cellar.  I really hope I can get some to sprout.  I have also read, the shoots (slips) need to be 1' long before planting outside and that they take a long time to grow so that is why I am starting early.