If you have free-draining soil in your garden, it’s safe for you to leave many of your root crops in the ground over the winter to harvest as needed in most climate areas. Parsnips, carrots, turnips, kohlrabi, beetroot and swedes are all able to be left in the ground over winter, usually without losing any of your crops to rot, disease, or pest infestations.
The foliage on the tops of the plants will likely die back, but the harvestable fruit that lies just beneath the surface of the soil will be just fine if left in the ground to harvest after winter has come and gone. Add a layer of mulch over them for extra protection against the elements. If you expect an extremely cold winter, with sustained temperatures of 25 degrees and below, it’s best to go ahead and harvest all of your root crops so as not to chance losing them due to freezing.
Beets can withstand temperatures around 30 degrees F for sustained periods. If beets are left in the ground throughout the winter, they will begin producing spring greens very early. Be sure to harvest your beets before they start to regrow these leaves, as the flesh of your beets will turn woody if you don’t harvest them in time.