For a few carrots, you can immerse them in cold tap
water and stick them in the refrigerator to make them crisp.
Kelda, he isn't really replanting them, he's just storing them
underground.
The requirements for root crop storage are cool, moist and dark. Having them easy to get to is also a nice asset. If you get much snow, it's a pain to get them from under two feet of it. Here in the PNW, leaving them in the soil is iffy because of the rot issue from the rain, and the freeze-thaw thing makes carrots sort of spongy. Besides, I own a canine Belgian Harvester, who pulls up carrots, and plucks blueberries and cherry tomatoes for her own consumption, and she LOVES carrots.
Here's some info that you might be able to adapt if you don't have a cool basement, from the National
Gardening Association:
http://www.garden.org/foodguide/browse/veggie/roots_harvesting/623 If you use sawdust, 'raw' sawdust is best, dried sawdust is next (furniture type), and it all must be untreated, so be sure you know your source. Here in WA, a cubic
yard (one picup load) of sawdust costs about $10. Sand costs twice that. Your area may be different, so call around and ask; landscaping materials yards seem to be the best.
I used to know a woman who harvested her root crops and packed them in moist sand or sawdust in clean 30-gallon garbage cans and left them on her enclosed but not heated back porch (north-facing). Be aware that these get VERY heavy and practically immovable, so carry the produce to the storage site.
Sue