If you are going to store carrots, cut off the tops. While the tops are on the carrots, they draw water away from the carrots themselves which will result in them wilting sooner. If your carrots do begin to wilt, cut a fresh end--if you have already cut off the top, take a little slice off the top and if you have not already cut off the top, cut it off. Then stand the carrot up in room temperature water with the cut end in the water. The carrot will absorb this water and get nice and crisp again.