Plant Parsnips for Winter Picking
A parsnip picked in September and simply boiled is bound to be bland, mushy and unappetizing. But leave the roots in the ground until Christmas time or even the following spring, exposed to frost and near-freezing temperatures, and by some alchemy of cold on carbohydrates, they become a different vegetable altogether—sweet, nutty and delicious. Parboiled and then oven-roasted until crisp-soft and caramelized, puréed alone or with potatoes, grated and fried in a version of potato pancakes or Swiss rosti, simmered slowly in a subtly spiced soup or hearty stew, parsnips (Pastinaca sativa) are as versatile as any vegetable and tastier than many. But you have to be patient.
Parsnip seed is slow to emerge and a 60 percent germination rate is considered good. The young plants take their sweet time sizing up and need an entire growing season to mature. And then there’s the long fall or full winter wait until the roots’ starches change to sugars
Where to plant parsnips
The best soil for parsnips is well-drained and moderately fertile, and any texture from sandy to heavier clay loam will do. Crumbly compost is a suitable fertilizer, but steer clear of manure, which can cause hairy, misshapen roots. Dig or till the ground as deeply as possible—a full 30 centimeters is good—removing stones as you go (if root meets rock it will branch and fork). Then rake the surface to a fine, smooth finish.
While parsnip roots are hardy enough to survive winter, the seeds themselves are thin, papery and as fragile as they look, so anything a gardener can do to facilitate germination will result in an evener row. As with carrots and parsley—both parsnip cousins in the Apiaceae (formerly Umbelliferae) family—the fresh seed is critical: those more than a year old will have lost all their vitality. Sometime during the week before or after the spring frost-free date, draw out a shallow furrow no more than 15 millimeters deep and plant seeds densely, at one per centimeter. If your soil is sandy, simply brush some over the seeded row and pat gently. In heavier soil, it’s prudent to cover the row with either sifted compost or sand, since crusted clay is hard for seedlings to breakthrough. Keep the ground moist and look for sprouts in two to three weeks.
When to harvest; cultivars
Since earwigs can clear a newly sprouted row in a couple of nights, my partner and I dust seedlings with rotenone powder to help them along their slow and steady way. Thankfully, parsnips are not bothered by any other insects later on.
“Sow thick, thin quick.” This old rule for radishes applies equally to parsnips. Once up and growing, about the time their leaves reach six or eight centimeters high, parsnips need to be thinned to their final spacing, roughly eight centimeters apart—if crowded, you’ll be left with shoestrings. A weekly soaking maintains continual growth and keeps the roots tender; weed as needed.
Harvest your garden-grown parsnips
In our snow-covered, Zone 4 garden, the earth seldom freezes to any depth and parsnips are an early springtime treat, dug the day after the white blanket melts away, and for the next several weeks. And dug they must be: you might pull carrots by hand, but even in sandy soil a parsnip root will have to be loosened carefully and lifted out with a spade.
Parsnips are biennial:
roots the first year, flowers and seeds the second. Fresh foliage begins to grow during spring’s first warm days, but the plump, white roots are at their best before new green leaves are very far along—a window of three weeks to a month, well before there is anything else to eat from the garden (except perhaps for Jerusalem artichoke tubers and dandelion greens).
In places where the soil routinely freezes solid, early November is the time to rake a mound of fall leaves, 20 to 30 centimeters deep, over the parsnip row to keep out the hardest frost. This simple protection enables you to sample some roots in December—nice chunks to roast with the festive bird. Those that remain will be sweet and ready first thing in spring.
Wild ancestors of today’s parsnips are thought to have originated in the Mediterranean region and spread throughout Europe, which is where modern parsnips were developed during the Middle Ages. Little has been done to them since then. Most catalogs list only a few cultivars: ‘Harris Model’, said to be “free of side roots,” and ‘Hollow Crown’ are two that are widely available. ‘Andover’ and the hybrid ‘Gladiator’ both have stronger tops (which is of more interest to commercial growers who harvest mechanically), and slightly higher sugar content, but any parsnip exposed to cold will turn sweet. All varieties are hardy across the land, even where the ground freezes deep and long, and all grow roots from 15 to 30 centimeters long.