The harvest period for most vegetables ends with the first hard frost. However, the quality of some root crops, such as parsnips and horseradish, actually improves with exposure to cool temperatures. Parsnips and horseradish should be harvested in late fall or early spring.
Cool temperatures convert starch to sugar and give the parsnips their distinctive flavor.
Gardeners should be careful when digging parsnips. Damaged or broken roots do not store well. Trim the foliage back to within 1 inch of the roots. If storing in the refrigerator, place the parsnips in perforated plastic bags. Parsnips can be left in the ground over winter and harvested in the spring.