We placed some potatoes that had many eyes and seemed to be getting real soft into our composite bin at backyard for the purpose of making good soil and providing the worms something to eat.  Then, as time passed, they started to grow leaves and big roots in the composite bin. We transplanted what was growing into a make shift flower pot added soil and water for a couple of months.  What you see in the picture is what we harvested potatoes first time from our garden.  Looks like we will try this again with potatoes that seem to be going soft and maybe we will harvest enough to sell @ the green market.