How to Overwinter Parsnips in 5 Simple Steps

You're missing out if you haven’t tasted a parsnip sweetened by winter’s frost. They’re comforting, versatile in the kitchen, and nutritious, perfect for winter soups and stews. Join organic farmer Jenna Rich as she shows how to overwinter parsnips in five simple steps.

Written by Jenna Rich Horticulture review by Sarah Jay Last updated: October 26, 2024 | 6 min read

A fresh pile of pale, elongated root vegetables identified as Pastinaca sativa, with thin, tapering bodies and light green leaves attached. The roots lie on a rustic surface, their slightly rough skin and creamy hue reflecting their freshly harvested state, surrounded by leafy greens.

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I mistakenly, but successfully, overwintered carrots (a parsnip cousin) a few years ago. They were sown a little late for my area of Zone 5b, so they weren’t ready to harvest before our last farmers’ market of the season. I covered them to protect them from deer and left them for the winter to see what happened.

Much to my surprise, massive, bright orange and sweet carrots remained in the ground in the spring. We pulled them up through the snow, shocked that voles didn’t destroy them throughout the winter. We sold them as winter-sweetened carrots at the first spring farmers’ market. We were surprised when very few people knew what this meant.

Studies show that harvested root vegetables are perceived to be sweeter when stored at cooler temperatures for seven days versus those freshly harvested or stored at warmer temperatures. The sweeter flavor is due to increased development and starch, sucrose, fructose, and glucose levels. Others prove sweetening can also occur pre-harvest, making the desire to overwinter parsnips part of my summer and fall to-do list.

I tell you this carrot story because carrots and parsnips are both members of the Apiaceae family and sweeten similarly. It’s worth noting that parsnips are typically cooked and not eaten raw. Now that I can overwinter carrots for an early spring harvest, I want to do the same with parsnips. A popular heirloom to use in stews, soups, and vegetable roasts is the ‘All-American,’ famously popular for its quick maturity and earthly flavor.

I believe parsnips are far underrated. Let’s discuss how to overwinter parsnips so you can taste homegrown, winter-sweetened parsnips.

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What Effect Does Frost Have On Cold-Hardy Vegetables?

Rows of vegetables with lightly frosted leaves, including frilly, purple-hued plants and bright green heads, blanketed in delicate white crystals from the frost. The soil is rich and dark, and the cold morning air is palpable as the frost shimmers on the leaves, accentuating the plants' resilience. — The increased sucrose, fructose, and glucose levels give them a much sweeter flavor.

To understand why you would want to overwinter parsnips, let’s first discuss what happens to them when they’re left in the ground as the ground freezes over and winter arrives.

In the summer, parsnips naturally store energy as starch, which may also play a role in stress defense. As the season transitions to fall and winter, starches convert the stored starches into sugar, which helps them defend themselves against new stresses that arise. The sugar acts as an anti-freeze, keeping the carrot from freezing through and cracking. The increased sucrose, fructose, and glucose levels give them a much sweeter flavor.

This process is similar to when we cure sweet potatoes and winter squash. As the moisture evaporates, the sugar becomes more concentrated in the flesh, making them taste sweeter. So, it may not be the cold weather that makes vegetables sweeter, but the changes inside make it seem sweeter to the consumer.

Why Leave Parsnips In The Ground Over Winter?

A vibrant garden brimming with a variety of leafy plants, each featuring distinct shades of green and varying textures. Some plants stand tall with feathery leaves, while others are more compact and bushy, growing in well-tilled soil under warm sunlight. — In areas where the ground does not fully freeze, you can leave them in the ground and harvest them.

In regions where frost occurs, some gardeners leave crops like kale, spinach, carrots, cabbage, and parsnips in the ground to experience the added sweetness. In areas where the ground does not fully freeze, you can leave them in the ground and harvest them throughout the winter as needed. While they might not be as sweet as in areas that reach lower temperatures, the plant will still convert some starch to sugars, making them taste sweeter.

Pro tip: Steam and mash some alongside potatoes for added nutrition in the winter months. Kids who are picky eaters may not even notice!

Here are five easy steps to overwinter parsnips.

Get the Timing Right

Close-up of hands delicately working the dark, fertile soil, creating small furrows for planting. The smooth texture of the soil contrasts with the roughness of the hands, which are gently cradling the earth, readying it for new seeds to be planted under the soft glow of sunlight. — Adjust this according to your region’s first anticipated frost date and your garden’s setup.

Work backward to find the best sowing date based on the seed packet’s maturity days, as you’ve done with other crops. Adjust this according to your region’s first anticipated frost date and your garden’s setup. If it’s your first time sowing parsnips, experiment with the timing and take notes for future years. Add them to your sowing schedule or garden journal.

Prepare the parsnip plot in an area that receives full sun and where the soil is rich and well-draining. A loose soil structure will help the plant form big, juicy, healthy roots. Use a mechanical seeder or hand sow ½ to ¾ inches deep into a two-inch wide trench. Cover them with soil and gently tamp them down for good seed-to-soil contact. Rows should be 12 to 18 inches apart to give each root enough space to grow and access to water and nutrients.

I like to cover the area with a piece of row cover to help keep the soil moist and protect the seeds from hungry birds and mice. Thin to three to six inches once germination occurs.

Water Consistently

A small patch of vibrant green seedlings emerging from dark, damp soil, being gently watered from the right. The delicate water flow nurtures the tiny sprouts, which are barely a few inches tall, with their tender leaves soaking up the moisture in the warm light. — They can take up to three weeks to germinate and require moist soil and seed-to-soil contact.

Water them daily after sowing them so the soil doesn’t dry out. Like carrots, parsnips can take up to three weeks to germinate and require moist soil and seed-to-soil contact for high germination rates. Once they germinate, water them frequently for short periods rather than infrequently for long periods. This deep watering method will keep the water from pooling and causing rot and splitting.

Established parsnips only need water in dry periods. Cut back watering amounts as the roots mature and as frost approaches. Your parsnips should be well-established with a robust root system before winter arrives.

Add A Thick Layer of Mulch

Small green shoots push through a layer of dried brown and orange leaves, signaling the beginning of new life. The forest floor is covered in fallen debris, but the fresh sprouts break through, creating a contrast between decay and renewal in this woodland setting. — Mulched leaves, compost, grass clippings, wood chips, and organic straw will all work.

Your goal for overwintering any crop is to keep the soil and air temperature around them as consistent as possible. Fluctuations cause stress and damage to plant cells and crops. The more vulnerable your plants are, the less likely they are to make it through the winter.

Whatever your preferred mulch material is will work for mulching parsnips. Mulched leaves, compost, grass clippings, wood chips, and organic straw will all work. The amount you add will depend on your growing zone and winter temperatures. In Zone 5b, I load up my overwintered veggies like garlic and carrots with about six thick layers of straw to help hold in heat and protect them from frost.

Protect From Critters

A meticulously organized garden bed showing a neat row of carrots with their bright green, feathery tops, adjacent to onion shoots and Pastinaca sativa with taller, broader leaves. The beds are separated by a wooden pallet pathway, and the plants thrive in the rich, brown soil under sunlight. — Plant a helpful companion nearby, like onions, garlic, or wormwood, to ward off hungry critters.

If you’ve ever had bite marks or crop destruction by voles, mice, or moles, I understand your pain! Nothing is more frustrating than sowing seeds, cultivating weeds, watering all summer and fall, and protecting them in winter, only to have them destroyed by hungry critters.

Plant a helpful companion nearby, like onions, garlic, or wormwood, to ward off hungry critters. Alliums will also help keep away flea beetles, aphids, and ants. Natural deterrents include coyote urine, chicken wire, fencing, motion-activated lights and sprinklers, proper spacing, and netting.

Consider adopting a barn cat or setting traps if your critter pressure is a severe problem. Contact your local pest control if you need further assistance.

Store Properly After Harvest

Long, slender Pastinaca sativa roots freshly pulled from the soil, their dark brown skin covered in traces of dirt. The vibrant green tops lay to the side, contrasting against the dark earth, emphasizing the harvest’s recent completion in a fertile garden. — Store unwashed with the tops removed in your refrigerator in a loose wrapping such as a paper towel or dish cloth.

To harvest in the winter:

Wait for a stretch of temperatures of 32 to 40°F (0 to 4°C).
An indication of when the sweetness has begun is when the tops have withered. Note that the tops may die back if you live in a region with harsh winters.
Gently pull them or use a fork. Use caution so you don’t puncture the roots.

To harvest in the spring:

When temperatures break, remove the mulch. Repurpose it by adding it around annual flower beds or into paths to keep weed pressure down.
Pull or fork them gently, as mentioned above.
Perform a mass harvest so no top regrowth is allowed. Doing so will get you the best quality roots and flavor.

Store overwintered parsnips unwashed with the tops removed in your refrigerator in a loose wrapping such as a paper towel or dish cloth. You want to wick away moisture that may shorten the shelf-life and allow them to breathe. Keep the humidity high and the temperature about 32 to 40°F (0 to 4°C).

Alternatively, store them similarly to carrots. Discard the tops and store them unwashed in a dry, cool place with high relative humidity. A root cellar is best, but you can also store them in sand in a basement or semi-heated garage.

An Important Note

A close-up of an arm showing a patch of red, irritated skin, with visible blisters and inflammation caused by contact with Pastinaca sativa or similar toxic plants. The background of green grass hints at outdoor exposure, with the irritated area displaying symptoms of phytophotodermatitis. — They contain a compound that may cause severe rash, blistering, and discoloration.

Gardeners with sensitive skin should wear long sleeves and gloves when harvesting and handling parsnips. They contain a compound that may cause severe rash, blistering, and discoloration, commonly called parsnip rash or phytophotodermatitis (PPD). The sun may exacerbate effects and cause sun sensitivity in affected gardeners.

Wash any parts of your skin that come into contact with parsnips or their tops to avoid rashes, especially if your skin is easily bothered.