Unless you want a really early harvest, we recommend waiting until the soil has warmed up in late April or even early May to sow parsnips. They are very slow to germinate and the extra warmth can really help. Sow three seeds every 15cm in rows 30cm apart, and thin to one plant per station. Pay particular attention to weeds during the early stages and you will get a fine crop.
Parsnips have been around Eurasia in a wild form since ancient times. Cultivated by the Romans, used as a sweetener before sugar was around, it has still many uses today and it can stay in the ground throughout the winter and turns remarkably sweet after the first frosts.