Areas of the country with mild winters should plant this vegetable only in the fall for a winter harvest. Cold weather and even a freeze improves the flavor of parsnips. Parsnip seeds are slow to germinate, so overnight soaking of the seed is recommended. You may want to consider marking the rows with radish seed. The faster germinating radish will have the advantage of breaking up any crusty soil while the parsnips are trying to break through the surface.
Parsnips requires small amounts of nitrogen and moderate amounts of phosphorous.
The use of fertilizers with plenty of potassium will encourage proper root development. In the spring when the tops begin to grow once again, harvest all remaining roots or they will become woody and loose their taste.