Vegetable · Apiaceae
Parsnip
Pastinaca sativa
Below the ferny green tops, a pale tapering root swells slow and turns sweet and nutty after one hard frost.
Full sun
Every 5–7 days
36–75°F · 2–24°C
100–130 days
Overview
The parsnip is a cool-season root crop in the carrot family, grown for the long, pale, tapering taproot it draws down into the soil over a long season. It is a biennial grown as an annual, lifted in its first autumn as a smooth ivory spindle rather than left to send up its flowering stalk the next year. The flesh is close-grained, starchy, and gently nutty, a root that has fed northern kitchens for centuries.
Above ground the plant is modest, a low rosette of ferny green leaves that stands only about 12 to 18 inches (30 to 45 cm) tall while the real growth happens unseen below. The root builds slowly from thin, papery seed, and it needs 100 to 130 days to fill out to a firm, blunt-tipped spindle. Cold deepens it further, since a hard frost draws the starch over to sugar and enriches the flavor within the pale flesh.
A fine parsnip is a matter of the ground and the wait. The taproot wants deep, loose, stone-free soil so it can run down straight and unbranched instead of forking into whiskered limbs, the bed stays moist while the slow seed stirs, and the harvest holds until frost. One thing to know at the touch: the leaves and stems weep a thin, clear sap that can burn skin in sunlight, so the tops call for a careful hand.
Care
The short version: parsnips want full sun and deep, loose, stone-free soil, about an inch of water a week for even growth, light feeding only, and a long wait to a frost-sweetened autumn harvest of pale, tapering roots.
Light
Parsnips draw the fullest, longest roots in full sun, though they will grow on in partial shade. Less light yields a shorter, slimmer root, so give them the brightest spot you have.
Water
Keep the soil evenly moist, about an inch of water a week, so the pale flesh swells smooth. Swinging between bone dry and soaked splits and cracks the root, and steady moisture matters most before emergence, when a dried, crusted surface can seal the fine shoots under.
Soil
The soil shapes the root more than anything else. Parsnips need deep, loose, well-drained sandy loam cleared of stones and clods to a depth of 12 to 18 inches, or the taproot forks into twisted limbs instead of a single clean spindle. Aim for a pH of 6.0 to 7.0.
Temperature
Parsnips are hardy across a wide band, roughly 36°F to 75°F (2°C to 24°C). The root sits out frost in the ground, and that cold is exactly what sweetens the pale flesh.
Humidity
Ordinary outdoor air suits them, somewhere around 40% to 70%, with nothing to manage on this front. Moisture in the soil is what shapes the root.
Feeding
Feed with a light hand, once at sowing and again mid-season, using a balanced, low-nitrogen fertilizer. Too much nitrogen or any fresh manure fuzzes the root with fine white whiskers and forces it to fork instead of running clean.
Pruning
Parsnips need no real pruning. Thin the seedlings to 3 to 4 inches apart once the true leaves unfurl so each root has room to swell, and cut off any flower stalk that tries to shoot up in the first year.
Size & spacing
The ferny tops stand about 12 to 18 inches (30 to 45 cm) tall and spread 8 to 12 inches (20 to 30 cm) across. Thin the plants to 3 to 4 inches apart in the row so each pale root has space to thicken.
When to plant
The parsnip fills out slowly beneath its ferny tops. Direct sow the thin seed in early spring, a few weeks before the last frost, once the soil is workable and at least 40°F (4°C), then let the pale root swell all season. Hold the harvest for late fall and through winter, since a hard frost is what turns the flesh sweet.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Direct sow in early spring, 2-4 weeks before the last frost, once soil is workable and at least 4°C (40°F); parsnips do not transplant well due to the taproot.
- Harvest: Harvest roots in late fall and through winter; flavor sweetens markedly after one or more hard frosts converts starch to sugar.
Hardiness
USDA hardiness zones: 2–9
Temperature: down to -46°C
Troubleshooting
Most of a parsnip's troubles hide below the soil, in the seed or the swelling root, and only surface when a root is lifted. A bare row or a twisted, scarred spindle traces back to the seed, the soil, or the weather. Match the look of the problem below, then settle the cause before next season.
Bare brown soil where fine green seedlings should stand
When the row shows nothing but flat brown soil, the cause is usually the seed itself, because parsnip seed is thin, papery, and short-lived, so carried-over seed rarely stirs. The seed also wants its full 14 to 28 days beneath a surface that stays dark and damp, since a dry, pale crust seals it under. Sow fresh seed each spring, keep that surface evenly moist until the first hair-fine shoots break through, and set quick radishes alongside to trace the line.
Fix:
- Sow fresh seed each season
- Keep the seedbed continuously moist until emergence
- Cover the row lightly to prevent crusting and interplant fast radishes to mark the row
A split, whiskered root instead of a smooth taper
A clean parsnip is a single pale spindle, so stones, clods, and heavy soil split it into forked, twisted limbs that snake around every obstacle. Too much nitrogen or fresh manure fuzzes the surface with fine white whiskers, and a transplant-jostled root deforms the same way. Dig the bed deep and lift out the rocks before sowing, keep feeding low in nitrogen, and sow the seed right where it will grow.
Fix:
- Cultivate and de-stone soil deeply before sowing
- Use low-nitrogen, well-rotted amendments only
- Direct sow rather than transplant
Sunken brown-to-black scars ringing the root shoulders
Brown-to-black patches that sink into the broad pale shoulders are canker, a fungal rot that settles into wet, poorly drained soil and enters through any crack or nick at the crown. In a wet season the dark, decayed tissue spreads wider and deeper. Improve the drainage, draw loose soil up over the exposed shoulders, and grow canker-tolerant types like Gladiator or Cobham Improved Marrow.
Fix:
- Improve drainage
- Hill soil over exposed shoulders
- Grow canker-tolerant cultivars such as 'Gladiator' or 'Cobham Improved Marrow'
Thin rust-brown tunnels scribbled through the pale flesh
Fine rust-brown lines scribbled through the pale flesh of the lower root are the galleries of carrot rust fly larvae, whose small adults hover about the ferny foliage in spring and again in late summer. Lay a floating row cover over the bed to keep the flies from the leaves, move the planting off last year's carrots and parsnips, and hold the sowing until the early flight thins out.
Fix:
- Cover rows with floating row cover
- Rotate away from previous carrot/parsnip beds
- Delay sowing to avoid peak fly flights
Toxicity
The pale parsnip root is a safe, wholesome food once peeled and cooked, and a stray nibble does not harm a pet. The hazard sits in the leaves and stems, which weep a thin, clear sap laced with furanocoumarins that can burn skin in sunlight, so handle the tops with gloves and keep animals from grazing the foliage freely.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
The ASPCA does not list parsnip as toxic to cats, and a nibble of the pale root is harmless. The watery sap that beads from a cut leaf is the concern, since it can leave the mouth or thin-furred skin sore, so a cat is best kept away from the green tops.
Dogs Mild
Parsnip stays off the ASPCA toxic list for dogs, and the cooked root is harmless. A dog that crushes the leaves releases the clear sap, which can irritate the mouth, and any that films onto bare skin stings once sunlight reaches it, so the foliage is best kept out of reach.
Horses Mild
Horses crop the ferny tops without much trouble, but the furanocoumarins in the leaf sap can leave pale, thin-skinned areas like the muzzle reddened and sore once the sun hits them. Look over any bare skin for irritation or peeling after time in the patch.
Rabbits Mild
A little parsnip is a fine treat for a rabbit, and the root causes no harm. The leafy tops carry the same irritant sap in their stems and veins, so they suit only small amounts at a time.
Livestock Mild
Cattle, goats, and sheep browse parsnip foliage without much trouble, though the sun-triggered compounds in the sap can redden or blister pale, exposed skin around the face. Heavy grazing of the green tops is the part to keep in check.
Birds Mild
Backyard hens peck at parsnip root and kitchen scraps without any problem. The leaves and stems hold the irritant sap, so fresh tops are best kept out of the run.
People Root safe, sap a hazard
The peeled, cooked root is a sweet, wholesome vegetable and safe to eat. The hazard is the thin, clear sap in the leaves and stems, which carries furanocoumarins that set off phytophotodermatitis, a painful sunlight-driven rash of blisters and lingering brown stains on the skin. Wear gloves and long sleeves when cutting or weeding the tops, and wash any sap off your skin before going into the sun.
Wear gloves and long sleeves when cutting, weeding, or handling parsnip tops and sap, especially in sun; wash skin promptly if sap contacts it and keep that skin out of sunlight. The root is safe to eat once peeled and cooked.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Parsnip varieties differ mostly in the shape of the root, its sweetness, and how well it shrugs off canker. These are the ones seen most often.
Hollow Crown
A long-rooted heirloom with broad shoulders and a dished, sunken crown at the top, one that only draws its full length in deep, stone-free soil it can bore straight down through.
Harris Model
A home-garden favorite whose smooth, uniform white roots carry a fine, close-grained texture and a reliably sweet flesh.
Gladiator F1
A vigorous hybrid that resists canker far better than most while still drawing smooth, even, chalk-white roots.
Cobham Improved Marrow
A sweet, canker-tolerant variety with clean, unblemished skin over medium-length roots that suit a wide range of gardens.
Companions
Parsnips do best near plants that mark their slow rows or keep the soil open, and worst beside relatives that share their pests.
Plant near
Radish: Fast-germinating radishes mark the slow parsnip rows and loosen the soil.
Bush beans: Legumes fix nitrogen and do not compete for the deep root zone.
Onion: Pungent alliums can help mask the crop from root-fly pests.
Keep apart
Carrot: Shares pests and diseases such as carrot rust fly, increasing pressure when grown together.
How to propagate
There is one way to raise a parsnip, from thin, papery seed sown right where the root will grow.
SeedModerate
Direct sow in early spring into workable soil · Germination takes 14-28 days; roots reach harvest size in about 100-130 days
A parsnip rises only from seed dropped straight into the bed, since the fragile taproot will not survive a lift. The seed is thin and papery and fades quickly, so a fresh packet each year sets the best stand, sown in early spring once the soil crumbles workable. The pale, hair-fine shoots can take 14 to 28 days to surface, so keep the bed evenly moist throughout, and the roots swell to harvest size about 100 to 130 days on.
Myths
Parsnips are just white carrots.
The pale, tapering shape suggests a kinship, but parsnip and carrot are different species, Pastinaca sativa and Daucus carota. The parsnip is the sweeter, starchier root, and its flavor turns richer once a frost has passed.
Parsnip leaves are safe to handle like any other garden green.
The leaves and their clear sap hold furanocoumarins, and once that sap films onto skin and meets sunlight it raises phytophotodermatitis, a blistering chemical burn. Handle the tops with gloves and covered skin, and keep any sap off bare arms.
Parsnips are inedible until they have been through a frost.
The root is edible at any point, frost or not. Cold simply converts a share of its starch to sugar, so a frosted root tastes sweeter rather than only then becoming safe.