To plant and enjoy a homegrown parsnip, you must live in the right growing zone. Parsnips are considered a winter vegetable because they must spend a month at near freezing temperatures in order to develop the parsnip flavor that you know and love. However, a reasonably cold winter is one of the parsnip's few demands. Once planted, this easygoing tuber can be virtually forgotten until nearly one year later when it is time to harvest the root.
Parsnips are hardy plants that are not picky about soil type. Simply choose a spot in your garden that receives a fair amount of sunlight. Then use a hoe to loosen the soil to a depth of 2 feet. Amend the soil by spreading 3 inches of aged compost before loosening the soil.
Plant parsnips in March. Bury the parsnip seeds 1/2 inch below the soil. Each seed should be roughly 1 inch away from its neighbor. Germination rates of parsnip seeds are notoriously low, so plant a little more than twice as many parsnips as you think you will need. Rows of parsnips should be 2 feet apart.
Cover the seed bed with 1 inch of aged compost.
Water the soil until it is quite moist. Continue to keep the soil moist until the parsnips germinate in roughly one month. Then only water them if there has been extended drought or if the soil is dry 3 inches beneath the surface. Parsnips are quite hardy and the occasional drink is all they will need until harvest time.
Thin parsnip seedlings to 4 inches apart when they are 2 inches high. Pull up the smallest sprouts (take care not to disturb the roots of neighboring plants) and compost them.