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Growing Parsnips: Planting, Growing, and Harvesting Parsnips | The Old Farmer's Almanac

Parsnips

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Martina Unbehauen/Shutterstock
Botanical Name
Pastinaca sativa
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How to Plant, Grow, and Harvest Parsnips

Catherine Boeckmann
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Parsnips are a hardy, cool-season crop planted in the spring, kissed by fall frost, and harvested before the ground freezes. Parsnips enrich soups and stews but can also be enjoyed as a side dish. Here’s how to plant, grow, and harvest parsnips in your garden.

About Parsnips

Parsnips, popular with ancient Greeks and Romans, were brought over to the Americas with the first colonists. A relative of carrots and parsley, parsnips are biennials even though they’re usually grown as annual vegetables. 

Parsnips need a long growing season and are best harvested after a few fall frosts; if planted too late in the season, their roots will be small. 

Parsnips lend nutty, sweet flavor to any dish, but these root vegetables can also be enjoyed by themselves as a side dish. (Roasting is a favored method!) Plus, they are packed with nutrients, like potassium and vitamins B6 and C.

Planting

Plant parsnips in a sunny area with loose soil that drains well and is free of rocks. As with carrots, clay or compacted soils can cause parsnip roots to be thin and misshapen. Make sure the area is clear of weeds. Loosen the soil to a depth of 12 to 15 inches and mix in a 2- to 4-inch layer of compost or aged manure for fertility.

When to Plant Parsnips

Parsnips need a long growing season, so sow seeds as soon as the soil is workable in the spring. Parsnip seeds will germinate in soil temperatures as low as 48°F (9°C), but ideally soil at 50º to 54ºF (10° to 12°C) will speed germination.

How to Plant Parsnips

Don’t plant where sod grew in the previous season. Excess nitrogen in the soil will cause overabundant top grow and poor root development. Consider doing a soil test.   

  • Always sow fresh seed. Parsnip seeds do not store well and seeds that are more than a year old will have a reduced germination rate.
  • Sow seeds directly in the garden. 
  • Sow seeds 1/2-inch deep, 1 inch apart, in rows 18 to 24 inches wide.
    • Tip: Sow radish seeds in between your parsnip seedings. Radishes will grow quickly, marking the row and breaking the dirt’s crust for the parsnips.
  • Parsnips are slow to germinate. Seedlings typically emerge in 2 to 3 weeks, or longer in soil temperatures below 50°F (10°C). To hasten the process, keep the soil moist.
    • Tip: Another way to speed up germination is to start by soaking paper towels or cotton wool pads.  Place them on a saucer and press papery parsnip seeds into them. Keep the seeds warm (50º to 54ºF) and watch for little white roots to appear. Then sow as described. Discard any seeds that fail.

parsnips

Growing
  • Once seedlings are 2 to 3 inches tall, thin them so that they’re spaced 3 to 4 inches apart. To avoid disturbing the delicate roots of the remaining seedlings, simply snip off the tops; do not pull seedlings.
  • Use row covers to deter pests such as carrot rust flies.
  • Always keep the beds free of weeds, especially when plants are young. Mulching suppresses seeds and retains moisture.
  • Water in summer if rainfall is less than 1 inch per week. Parsnips need a fair amount of moisture to form healthy roots. 
  • As long as you started with good soil, fertilizing is likely not necessary. Excess nitrogen will encourage top growth instead of root growth.
  • Once roots start to form, hill soil around the plants’ base to prevent greening of the roots’ shoulders.

Note: Be careful about handling parsnips, as the sap and/or leaves can be irritating to the skin. Wear long pants, long sleeves, and gloves when weeding or harvesting.

Harvesting

Parsnips mature in about 16 weeds after planting, depending on the variety. Harvest when roots are at least 1 inch in diameter.

When exposed to near-freezing temperatures for 2 to 4 weeks in the fall/early winter, the starch in the root changes into sugar, resulting in a strong, sweet, unique taste.

  • Leave your parsnips in the ground for a few frosts, but harvest before the ground freezes.
  • Or leave them in the ground for the entire winter, covered with a thick layer of mulch. Harvest immediately after the ground thaws in the spring, before top growth starts. If a flower stalk develops, roots may turn woody. 


Credit: Deyan Georgiev/Shutterstock

How to Store Parsnips

Before storing parsnips, trim foliage down to 2 to 3 inches. Store parsnips between 32 and 35°F (0 and 2°C), with a humidity of 90 to 95%. For longer-term storage (4 to 6 months), store roots in slightly damp sand, sawdust, or leaves.

Wit and Wisdom

Soft words butter no parsnips, but they won’t harden the heart of the cabbage either.
–Irish proverb

Pests/Diseases

Parsnip Pests and Diseases

Pest/Disease Type Symptoms Control/Prevention
Aphids Insect Misshapen/yellow leaves; sticky “honeydew” (excrement); sooty, black mold Grow companion plants; knock off with water spray; apply insecticidal soap; put banana or orange peels around plants; wipe leaves with a 1 to 2 percent solution of dish soap (no additives) and water every 2 to 3 days for 2 weeks; add native plants to invite beneficial insects
Black (Itersonilia) canker Fungus Shallow, reddish brown/purple/black cankers form on crown and/or shoulder of root; small, orange-brown spots on leaves may have green halos Choose resistant varieties; cover exposed shoulders of roots with soil; rotate crops
Carrot rust flies Insect Wilted/stunted plants; tunnels with rust-color excrement in roots; root rot Monitor adults with yellow sticky traps; use row covers; add native plants to invite beneficial insects; destroy crop residue
Leaf miners Insect Meandering blisters in leaves caused by tunneling larvae Remove infested leaves; weed diligently; use row covers; till soil early in season; rotate crops
Cooking Notes

Parsnips and carrots are wonderful when roasted together with rosemary on a baking sheet. The cores of a parsnip can be a little tough. When roasting, we recommend cutting parsnips at an angle into disks. 

One of our favorite ways to enjoy parsnips is by pureeing similar to mashed potatoes. They have a sweet and rich flavor and aren’t as high in starch as potatoes. Steam first and then add to your food processor.

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