How Do I Grow Parsnips?
Parsnips are cool-season root vegetables that are similar in appearance to carrots but with their own unique growing requirements and distinct taste. Parsnips that have experienced a few touches of frost prior to harvest are the sweetest, with a nutty or earthy flavor. If you want to grow parsnips in your garden, here is everything you need to know.
You can also download my How Do I Grow Parsnips? one-sheet and keep the free resource handy for your reference.
Parsnips are in the carrot family which also includes carrots, celery, dill, fennel, coriander, cumin and parsley. The family is also known as the umbellifers because the plants have umbrella-shaped flowers.
Some common parsnip varieties grow just half a foot deep while others can reach depths of up to 3 feet or more, so a lot of food can be grown in a small footprint. Roasted parsnips can be prepared with various herbs and spices or something sweet, like maple syrup. Parsnips can also be pureed to make soup and casseroles and can even be mashed or fried.
Where, When & How to Plant Parsnips
Parsnips should be planted in a bed that receives full sun, but they can tolerate a little shade from taller crops.
Because parsnips are root vegetables that can grow to great depths, prepare the planting bed by loosening the soil to a foot deep (more or less depending on the varieties you are growing). Remove rocks, twigs and other hard objects in the soil as well as any weeds that will compete with the parsnip taproots.
The soil should be well drained and fertile. Mixing in compost will help sandy soil to hold moisture better and will help clay soil to drain better. If you have clay soil, be very generous with how much compost you add, and mix it in deep. The soil pH should be somewhere between 6.0 and 7.0, which is slightly acidic to neutral. A soil test will let you know the pH and how to adjust it, if necessary.
Always use fresh seed from a trusted source. Parsnip seeds that are more than a year old will have a very low germination rate, if they germinate at all.
For cooler climates: Directly sow parsnip seeds in the garden as soon as the soil is workable in spring or once the soil temperature has reached 50°. (You can use an inexpensive soil thermometer to take a reading.) The seeds will germinate best when the soil temperature is between 50° and 70°F. Even under ideal conditions, parsnips take quite a while to germinate and a long time to mature — so don’t delay seed sowing. Expect germination after two to three weeks in this temperature range and even longer in cooler soil.
For warmer climates: In regions where the ground does not freeze in winter, parsnips seeds may be sown around July 1, give or take two weeks, for a winter harvest. You’ll want the parsnips to experience that winter cold so they naturally sweeten up. Some varieties can be overwintered in ground and then enjoyed in spring.
Sow seeds a half-inch deep and a half-inch apart in rows spaced 18 to 24 inches apart, to account for the top growth. Once seedlings grow to a couple of inches tall, thin the plants to one every 4 to 6 inches to allow them to grow to their full potential.
Parsnips can be interplanted with radishes, which will mature faster and be harvested and out of the way while the parsnips are still small. The radishes also help to loosen up the soil to the benefit of the parsnips.
All parsnips are from the same species of plant, Pastinaca sativa, and are white to cream colored inside and out. When selecting varieties for your garden, consider if they are suited to your region, whether they will have adequate time to mature and how big they will be.
Albion is a hybrid variety intended for fall harvest that has won an RHS Award of Garden Merit. It matures in 120 days from seeding. Harvest once the taproot has reached between 10 and 12 inches.
All-American is an heirloom parsnip that matures in as few as 95 days. The taproots are 3 inches across at the top and a foot long. All-American parsnips can be overwintered in regions where the ground does not freeze.
Gladiator is known for quick germination. It is a hybrid variety that matures in 110 days. Harvest at 7 inches.
Javelin is a hybrid variety intended for overwintering and a spring harvest. It matures in 110 days at 10 inches.
Sabre is a hybrid parsnip that can grow to be 5 feet, believe it or not, though achieving that length requires growing in a very tall container full of loose soil.
The Student is an heirloom parsnip that originated in England and has a long history. In ideal soil, it can grow 3 feet deep, though in most gardens it will be ready for harvest by the time it reaches 15 inches. It matures in 95 to 125 days.
Tender and True is an open-pollinated RHS Award of Garden Merit winner that matures in 150 days. This variety is intended for fall or winter harvest and can grow to a great length.
Warrior is a hybrid parsnip with large, cylindrical taproots that resist canker. It matures in 105 days and should not be overwintered. Harvest at 11 inches.
White Spear is an open-pollinated parsnip known for uniformity and vigorous growth. It matures in 120 days and is best harvested when the taproot is 11 inches.
Parsnips sprout and grow best in moist but not wet soil. In loamy soil, apply an inch of water each week if Mother Nature hasn’t done the job for you or falls short. In quick draining, sandy soil, aim for 2 inches per week, counting both rain and supplement watering.
When the daytime air temperature has warmed to more than 70°, you can apply a light organic mulch such as straw to protect the plants from the heat and retain moisture between waterings. A 2-inch mulch layer is sufficient and has the added benefit of suppressing weeds from sprouting.
Parsnips shouldn’t require much in the way of supplemental fertilizer if grown in soil that is rich in organic matter. When parsnips are in want of nutrients, their green tops will be stunted and pale. Side dressing with a light application or two of balanced organic fertilizer will resolve this. Avoid high-nitrogen fertilizers, which will cause the taproots to split.
Parsnip Pests & Diseases
To avoid many parsnip pest issues and to prevent diseases spread by those pests, apply floating row cover over your parsnips at planting time. Row cover is a physical barrier that will allow light and water through while preventing pests from landing on your parsnips and laying their eggs.
Parsnips are also a host plant of beneficial black swallowtail butterflies, which are also known as parsnip swallowtails. To provide alternate host plants, you can plant parsley, dill or fennel elsewhere in your garden. When you discover swallowtail caterpillars on your parsnips, move them to the herbs.
Willow-carrot aphids are sap-sucking insects that attack the parsnip foliage. They are pale green or yellow and they come for parsnips in the summer. They can spread mosaic virus, parsnip yellow fleck and other plant diseases to your parsnips. Keep aphids at bay with row cover. If you do find aphids on your plants, control them with a sharp blast of water. Once they are knocked down this way, they won’t be able to get back on the plants. Lady beetles, green lacewings and syrphid flies are all beneficial insects that prey on aphids. Refrain from using pesticides that will kill these beneficial predators as they kill pests.
Carrot rust fly is a pest of carrot family crops. The adults are less than a quarter inch long with black bodies and orange heads. They are active in May and June. The females lay their eggs on the soil near the base of plants. When the eggs hatch, the larvae feed on parsnip roots. Carrot rust fly larvae and pupae can overwinter in soil or in roots, so practice crop rotation if carrot rust flies have affected your plants. That means refraining from planting parsnips and other carrot-family plants in the same space each year.
Cutworms, of which there are several species, feed on roots and stems. The larvae overwinter as eggs or larvae, so row cover won’t resolve a cutworm issue. If cutworms are a known problem in your garden, turn up the first couple of inches of soil two weeks before planting time to expose the larvae to birds, which will reduce the number of overwintering pests significantly.
Armyworms are moth larvae that bore into parsnips. Handpick eggs on stems, under leaves and on fruit, and pick caterpillars, which may be green or black and gray. Bt is an organic control for moth and butterfly larvae that is safe around humans and pets and will not harm other wildlife. Because parsnips are hosts of swallowtail butterflies, row cover using row cover from the day parsnips sprout is a better choice than Bt.
Parsnips can be affected by various blight pathogens as well as mosaic viruses and root rot fungus. Aside from keeping pests at bay to stop them from spreading pathogens, the best prevention for parsnip diseases is crop rotation. If you plant umbellifers in the same spot for several years, pathogens will build up in the soil. Instead, wait four years before planting carrot family crops in the same spot again.
Wild parsnips are known to cause skin rashes, and some people experience irritation when handling cultivated parsnips. To be on the safe side, wear gardening gloves when harvesting parsnips. Grab the foliage firmly in a bundle, and pull up while twisting.
Parsnips will be ready to harvest after the varieties you are growing have reached or surpassed their days to maturity. The crowns should be 1 to 2 inches in diameter, or even bigger, depending on the variety. If they are smaller than expected, check again in a week. When the crowns have reached full size, pull up just one parsnip to determine if it has grown to the length you were expecting. If it has, your parsnips are good to go. If it hasn’t, your parsnips may need more time in the ground, or it may mean that they struggled in your soil to grow to their full potential.
Delay harvesting until after a few frosts. The cold will cause the starches in the taproots to turn into sugars, and the parsnips will taste that much sweeter. Harvest all of your parsnips before the ground freezes. (Deeply mulched parsnips can stay in the ground longer than bare crowns.) If you live in an area where the ground does not freeze, you can use your garden as your refrigerator. Then you can pull up parsnips all winter and into the spring when you need them.
Parsnips set seed in the second year and become woody as they do. These parsnips are no longer suitable for eating.
Parsnips may be enjoyed fresh or can be stored in a crisper drawer or a root cellar for a few weeks. Cut off all but a half inch of the foliage before storing but do not wash the parsnips until they are ready to be served. They can also be frozen or canned.
What are your secrets to growing parsnips successfully? Let us know in the comments below.
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Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
Episode 022: The Year-round Vegetable Gardener with Niki Jabbour
Episode 99: Understanding Crop Rotation: The Basics and Beyond, with Jack Algiere
Episode 195: Identifying and Controlling Garden Pests Organically
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How Do I Grow Parsnips? one-sheet
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