Growing parsnips is a much less common activity than growing something like tomatoes or corn. Native to Eurasia, parsnips have been a human food source for thousands of years. They were valuable enough that the Roman emperor Tiberius accepted them as tribute from the German tribes in the 1st century A.D. Parsnips, like beets, are loaded with plant sugars, and Europeans used them for sweetening before sugar beets became more widely available. French and British colonists brought them to America. Most varieties look like oversized, cream-colored carrots, although there are also round versions. The leaves can irritate the skin and cause discoloration that persists for months; wear long sleeves and gloves to weed around or harvest parsnips.
Biennial, the plant forms seedheads like a carrot and can become invasive in the right conditions. Most gardeners grow them as annuals, planting in spring and starting to harvest in fall. They tolerate frost very well and become sweeter if stored in the ground through the winter. The seeds don’t store well and germination of older seed is very poor, which is another good reason to treat them as annuals. Just leave a few in the ground and harvest the seeds the next spring. It’s a good idea to stake the seed stalks, as they are tall and heavy. If you have to, you can try storing well-wrapped seeds in the freezer, but plant very thickly to offset the low germination rates. Like their carrot relatives, parsnips are slow to germinate – expect at least two or three weeks before seedlings appear. Make sure to keep them moist during germination. You want fertile soils for growing parsnips but excess nitrogen makes for top growth instead of root growth. Grow parsnips in loose soil so the roots can have 12 to 15 inches of room. It’s worth the effort to dig trenches and sift the soil to remove rocks, as the roots will fork or become misshapen in rocky soil. Sow them about ½ inch deep, two or three seeds to the inch, and then thin to four to six inches apart by clipping the tops rather than pulling out seedlings. Once the roots start to bulk up, hill them like potatoes to keep them from turning green. If given more space (say a foot or more), parsnip roots will grow very large, but I think the smaller ones taste better. Either harvest before the ground freezes or mulch them heavily to store through the winter. You can also store in a root cellar, packed in damp sand, sawdust or leaves.
The parsnip is loaded with minerals such as calcium, manganese, magnesium, phosphorus, iron, zinc and especially potassium. High in fiber, they also contain a number of vitamins, especially folate, which is so important in preventing several kinds of birth defects. All of these goodies are most heavily concentrated just under the skin, so wash them but don’t peel.
Sorting out the history and development of heirloom parsnip varieties is complicated because the same term was used for both carrots and parsnips way back when. In addition, the original carrots were not orange but yellow-beige. It was not until 1393 that an herbal first made a clear distinction between the two vegetables. In addition, parsnips are biennial plants and insect-pollinated, so keeping distinct varieties going took a lot more effort than with something like self-pollinating annual beans or tomatoes. Three distinct types were in cultivation by the middle of the nineteenth century. The coquaine was a long, smooth parsnip grown primarily in France, although it was developed in Holland. The noisette Lisbonaise is of French origin, and is a short, rounded version that is reminiscent of a turnip. William Woys Weaver mentions another French variety called the Siam parsnip, which was yellow-rooted – I can’t find any other information on it.
- All-American – this long tapered variety is high in sugar and stores well. Creamy white and fine-textured, it is a high yielding variety.
- Harris Model – another long slim version, it has no side roots.
- Hollow Crown – developed in the early 1800s. This one is generally considered the best all-around variety.
- Kral Russian – this has small, round beet-shaped roots, which makes it a good choice for shallow soils.
- Guernsey Half Long – Introduced prior to 1850 (Weaver says 1826), this one is considered to have very good flavor. It is not as long as other varieties, so can be grown in more shallow soils.
- The Student – created in England by crossing a wild parsnip with a garden variety. Professor Buckman of the Royal Agriculture College at Cirencester, England, gets the credit for this one. He gathered wild seed from the Cotswolds in 1847 and made selections of resulting crops through 1859, when The Student was released commercially. It is a consistent producer and stores well. It’s also well-suited for heavy soils.