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Growing parsnips in a home garden takes some planning, but the reward is nutritious root vegetables ready for harvest when the rest of the garden is slowing down in the fall and winter or before it has gotten started again in the spring. In fact, after parsnips greens are kissed with a frost or two in the fall the roots are even tastier. If you’re not able to harvest them right away, these hardy root vegetables can overwinter in the garden. Parsnips (Pastinaca sativa) are a bit more finicky to grow than other vegetables in the carrot family, but they’re absolutely worth planting in a home garden. This article will give you the details you need to create the perfect conditions for growing parsnips as well as a caution about parsnip-plant lookalikes.
Why you should be growing parsnips
Besides their delicious flavor, there are several reasons why you might want to grow parsnips:
- A 10-foot row of parsnips can produce 5 to 7 pounds of roots in a season. That’s plenty to make several parsnip meals.
- After harvest, parsnip roots store well after harvest in the refrigerator or in a bin in the root cellar.
- Parsnips are low in fat and high in fiber, making a tasty and nutritious ingredient for stews, root-vegetable bakes, casseroles, soup, and other warm and filling meals.
- Parsnips mature in cool weather, giving life to your garden after many plants have transitioned out.
- If you’re looking for a gardening challenge, growing parsnips may provide that for you. When you get these exacting root vegetables right, you will know you’ve built excellent soil structure and your watering routine is on point.
When to plant parsnips
Parsnips are cool-season root crops. Parsnip seeds germinate best at a soil temperature of 55 to 65 degrees F, though they can germinate between 40 and 80 degrees F. You’ll have the most success growing parsnips when air temperatures are below 75 degrees F. Hotter temperatures reduce plant growth and cause the roots to develop a bitter flavor. On the other end of the thermometer, temperatures down to freezing won’t damage plants. Any colder, and you should give them a mulch layer.
Prepare the garden for growing parsnips
As root vegetables, parsnips prefer fertile, well-drained, deep soils. Amend heavy soils with compost or composted manure and deep digging. Parsnips prefer sandy soils over a heavy clay structure.
Pay attention to the weeds in your garden before you begin growing parsnips. Wild parsnips (Pastinaca sativa L.) are a garden-parsnip lookalike. While their roots are edible, the sap in their leaves and stems contain furanocoumarin, a compound that can cause a skin rash and photosensitivity. If you think you have wild parsnip in your garden area, handle it with care, wearing gloves and long sleeves. Be sure to not allow this weed to go to seed, because while its yellow umbellifer flowers are pretty—they look like dill flowers—the resulting seeds will fall and create more wild parsnip plants next season. Don’t intentionally sow parsnip seeds in an area with a wild parsnip population. They are hard to differentiate, and you don’t want to confuse the two.
How to sow parsnip seeds
Parsnip seeds are notoriously slow to germinate. Even under the best conditions, they may take 3 weeks to emerge. Sow seeds directly into the garden. Use care to not let them dry out, as a dry crust on the soil surface can prevent the parsnip seedlings from breaking through. Try covering the bed or planting container with floating row cover or a burlap sack and watering the fabric so it holds moisture close to the soil and the seeds until germination. Sow parsnip seeds at a 1/4-inch depth. Better yet, sow the seeds in a line on the soil surface, then cover them with compost or fine sand. Space rows 12 to 18 inches apart.
It’s important to note that parsnip seeds don’t remain viable for long, losing their vigor after one year. Growing parsnips requires you to start with new seeds each season.
Thinning the plants
Growing parsnips in densely seeded rows cuts down on weeds. Over-seeding the rows will also help ensure you get a good crop, accounting for parsnip seeds’ low germination rate. Sow more parsnip seeds than you think you’ll need, and thin the parsnips to 3 to 6 inches as they grow.
Caring for parsnip plants
Parsnip-plant care includes careful watering and paying attention to soil nutrients. Regular watering will benefit parsnips’ growth and development. Overwatering parsnips can cause hairy roots and forking. Fluctuations in watering can cause root cracking, other root disorders, slow leaf growth, and a bitter flavor. Depending on your soil type, parsnips may require up to 2 inches of water each week. Drip irrigation and mulch are smart water-conserving methods for growing parsnips.
Give your growing parsnips a boost with an organic fertilizer 6 weeks after emergence and another application 4 weeks after that. Side-dress the row with the amount recommended on the package.
When and how to harvest parsnips
Harvest parsnips when roots reach full size. This is usually 100 to 120 days from seeding, but if you’re not sure of the days to maturity for your chosen variety, check the seed packet. Let parsnips overwinter in the garden under leaves or other heavy mulches. When you’re ready to harvest the parsnips in the early spring, their stored starches will have turned to sugar, and the parsnip roots will be even sweeter and more tender. Just be sure to harvest them before the parsnip greens start their spring growth, or the roots can become woody. Parsnips are biennials, so at this point in their second year of growth, they are setting the stage for bolting—putting their energy into sending up a flower stalk and setting seeds.
When ready to harvest, use a digging fork to loosen the soil. Grasp the parsnips where the greens meet the root, and pull straight up, careful to not break off the end in the soil. After harvest, separate the roots and the greens. Wash and dry the roots, and store them in the refrigerator drawer for up to 4 weeks or in moist sand in a root cellar or cool basement for a few months. Harvested roots need high humidity to maintain their crispness. In storage, parsnips are sensitive the ethylene, the gas that apples and pears give off. Store parsnips away from tree fruits, or the parsnips’ taste can turn bitter.
Extra tips for growing parsnips
As a member of the Apiaceae family, parsnips are susceptible the same pests as their more familiar garden-vegetable relatives: carrots, parsley, celery, and fennel. A few parsnips foes to know include:
- Aphids – Aphids are an insect pest that infect many different species of garden vegetables. Willow-carrot aphids infect parsnips. Spotted early, you can pick off these soft-bodied insects from the parsnip leaves and dispose of them. A strong spray of water can knock off larger populations from mature parsnip greens. An insecticidal soap or oil could be a final measure of aphid treatment.
- Carrot fly – Also known as the carrot rust fly, you’ll know if carrot flies are bothering your parsnips by the tunnels they dig through the roots that are filled with rust-colored mush. Adults are small, dark flies, and larvae are tiny white maggots. Row covers over parsnip plants can keep adult flies from laying their eggs on the plants. If you find you’re having a carrot rust fly problem, harvest your parsnips in the fall so the insects don’t have a place to overwinter in the garden.
- Parsnip canker – Caused by the same fungus that causes silver-colored leaf spots, root canker prevention includes avoiding wet storage conditions.
Ready to grow parsnips?
From proper garden preparation to thoughtful seeding and a structured watering routine, growing parsnips will keep you on your toes in the garden. Parsnips are a great crop to stretch your garden muscles, and once you get the hang of growing parsnips, each season will become easier still.
Now you have an idea of how to best start these cool-season root vegetables, how to avoid their wild parsnip cousins, how to fertilize and water for the best root development, how and when to harvest, and even what to look for among parsnip pests. In no time, you’ll be ready when the humble parsnip gets its moment in the spotlight.
For more information on growing root vegetables be sure to read these in-depth articles:
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