Dig up whenever carrots reach desired size. Smaller carrots are more tender and sweeter than larger carrots.
Storage and Preservation Methods
Can, freeze, or dry.
Common storage methods: in root cellar, refrigerator or stored in the ground.
If you choose to store your carrots in the ground, put a thick mulch of straw, leaves, etc over the carrot tops to keep them from freezing. Heavy duty garbage bags full of dry leaves also work well.