The parsnip, a creamy-white root vegetable, requires a long growing season to fully mature. This biennial plant is cultivated as an annual, focusing its energy into developing a substantial, edible taproot in its first year. The time from planting the seeds to harvest spans between 90 and 150 days, depending on the variety and local climate. Parsnips thrive in cooler weather and need consistent growth to achieve their characteristic size and flavor.
Starting the Seeds
Growing parsnips requires direct sowing, as the delicate taproot makes transplanting difficult. Plant seeds in early spring, typically two to three weeks before the final expected frost. Always use fresh seeds because viability drops rapidly after one year.
Optimal germination occurs between 55°F and 65°F soil temperature. Sow seeds shallowly, about a quarter to a half-inch deep, and keep the soil consistently moist. Parsnips are slow to emerge, often taking 14 to 21 days for the first seedlings to appear.
The planting area needs thorough preparation since the root can grow up to 15 inches long. The soil must be loose, deep, and free of stones to prevent the root from becoming misshapen. Incorporating compost helps create the fertile, well-draining environment needed for straight, uniform roots.
Ongoing Care and Maintenance
Once seedlings emerge, focus on thinning and weed management for optimal root development. When plants reach two to three inches in height, thin them so remaining parsnips are spaced three to six inches apart. Instead of pulling unwanted seedlings, snip them off at the soil line to avoid disturbing the roots of neighboring plants.
Weed control is important because parsnips are poor competitors. Maintaining a weed-free environment prevents competition for water and nutrients, which is crucial for the slow-growing root.
Parsnips benefit from consistent moisture but do not require heavy fertilization. Excessive nitrogen encourages lush top growth at the expense of root development. Consistent, uniform watering prevents roots from splitting or cracking and ensures a smooth, healthy structure.
Harvest Timing and Storage
The full growth cycle extends into autumn, reaching maturity 100 to 150 days after spring planting. Maturity is indicated when the plant tops begin to die back, showing the root has reached its full size, typically at least an inch in diameter. The most desirable flavor, however, is achieved by delaying harvest until after the first few hard frosts of late fall or early winter.
Exposure to near-freezing temperatures initiates a biological process within the root. The cold triggers the plant to convert stored starches into simple sugars. This conversion significantly sweetens the parsnip’s flavor, giving it a characteristic nutty sweetness.
To harvest, carefully loosen the soil around the root with a digging fork to avoid breaking the long taproot. After digging, trim the green tops down to about half an inch to prevent foliage from drawing moisture during storage. Unwashed parsnips store best in cool, dark conditions (32°F to 40°F) with high humidity, where they can last for several weeks.