In 8b, SP's should be hardy. You could put that back in the ground, broken up a bit if desired, to get started early on some super-size spuds for next year. Whenever I dig up ones that I consider too small, I just put them back in the ground. Cuttings should take root in 2-3 days. When frost zaps the foliage, add compost to the area to enrich/improve the soil. The speed of development is a direct result of moisture & fertility, and texture of soil. If the ground is hard, it will be more difficult for a potato to expand. Continuing to add organic matter to the soil surface periodically will, over time, turn sandy or clay dirt to rich, dark, fluffy, fertile soil.
