Parsnips are a crop that will really stand up to the cold. As a matter of fact they will taste better after a frost or two. With an eye to the future you can plan enough to leave in the garden all winter, and harvest at will or as needed.
Sow seeds early, as soon as you can get out and work the soil without creating a mud pit. In the same way you might prepare the soil for peas in the fall, you can do for parsnips. Then on a nice spring day you can just go out to the garden and sow your seeds, without having to muck around with the ground. Since this crop may be in the ground throughout summer and winter select a location where water will not pool up or stand. We want good drainage.
Parsnips grow like carrots, a long root reach deep into the soil. For this reason we want a very soft soil that is free of rocks or other roots. It is worth the effort to dig out a foot deep trench and then fill it with light airy and sandy loam that is rich in compost and nutrients. You don’t want your thick long root malformed because it had to grow around a rock!
Parsnip seed is slow to germinate. Sow the seed sparingly and if possible in marked locations, otherwise you will need to thin. Either way is fine, and if you sow thickly you may wind up with a larger crop after you thin them out. Shoot for having plants at least 6 inches apart.
As mentioned, parsnips can stay right where you grow them throughout the winter. Sometimes you’ll have frozen ground and you can’t get the parsnips out without damaging them. You can store them if you wish. Go ahead and store them in the same manner you would for turnips, carrots or beets.