Once the tops have frozen, mulch over the row to keep the ground from freezing so hard that you can't dig the vegetables. Label your rows so you can find what you want when snow covers the ground. If you don't store these root vegetables in the garden, dig them before the ground freezes. Remove excess soil, cut off stems, and store in a pit or storage cellar. Beets will not keep as long as carrots.
Parsnips develop better flavor after several weeks in cold, moist conditions.