Parsnips thrive in soils that are rich, light, and deeply worked.  Sow seeds early in the spring, ½ inch deep, two to three seeds to the inch, in rows spaced 24 inches apart. Thin out plants to stand six to eight inches apart in the row. The flavor of parsnips is greatly improved by freezing as this helps convert the starches to sugar.

All American
130  days — The flesh is fine-grained, tender, and white with a  sweet flavor.  The roots are uniform and smooth with shoulders that are thick, 2½ to three inches across and tapering to ten to twelve inch long.  This variety has high a sugar content and stores well in the root cellar or the ground.

Harris Early Model
85-90  days — 3½ inches in diameter by up to twelve inches long with nearly no hollow crown. The flesh is white and tender and because it has little side shooting, is easy to pull.

Hollow Crown, Long Smooth
95-120 days — Twelve inch long tapering root, two to three inches thick at the shoulders. Being exposed to outdoor frost adds extra sweetness.

Although not a parsnip, this variety of parsley is grown for use as a table vegetable like parsnips.  It is included here for that reason.

Hamburg Rooted Parsley (Petroselinum hortense)
90 days — This is used differently than other parsley plants.  Also known as Hamburg Turnip or Parsnip, Hamburg Rooted Parsley is generally grown for its eight to ten inch long and up to two inches in diameter, fleshy white, parsnip-like roots.  The deeply cut leaves can also be used, like standard parsley, as a seasoning and garnish.  Stores well.  This is a pre-1600s variety.