A hardy biennial, Pastinaca sativa, of Mediterranean origin belonging to the plant order Umbellales. The parsnip is grown for its thickened taproot and is used primarily as a cooked vegetable. Propagation is by seed; cultural practices are similar to those used for carrot, except that a longer growing season is required. Parsnip seed retains its viability only 1–2 years. Harvesting begins in late fall or early winter, usually 100–125 days after planting. Exposure of mature roots to low temperatures, not necessarily freezing, improves the quality of the root by favoring the conversion of starch to sugar.