Vegetable · Apiaceae
Parsnip
Pastinaca sativa
Sow it, wait, and let a hard frost do the last bit of work, and the parsnip turns sweet and nutty under the soil.
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 pale, tapering taproot it builds underground over a long season. It's a biennial that gardeners treat as an annual, lifting the root in its first autumn rather than letting it flower the next year. Sweet, starchy, and a little nutty, it has fed northern kitchens for centuries.
Patience is the price of admission. The seed is slow and short-lived, the plant grows at an unhurried pace, and the roots need 100 to 130 days before they're worth pulling. What you get in return is a vegetable that actually improves with cold, since a hard frost turns its starch to sugar and deepens the flavor.
Growing a good parsnip comes down to the soil and the wait. Give it deep, loose, stone-free ground to run straight down through, keep the bed moist while the slow seed wakes up, and hold off the harvest until the frosts arrive. One caution travels with the crop: the foliage and sap can burn skin in sunlight, so the tops want careful handling.
Care
The short version: full sun and deep, loose, stone-free soil, about an inch of water a week to keep growth steady, light feeding only, and a long wait through to a frost-sweetened autumn harvest.
Light
Parsnips want full sun for the biggest roots, though they'll put up with partial shade. Less light just means a smaller harvest, so give them the brightest spot you have.
Water
Keep the soil evenly moist, around an inch of water a week. Swinging between bone dry and soaked makes the roots split and crack, and steady moisture matters most during the long stretch before the seed comes up, when a dried, crusted surface can stop germination cold.
Soil
This is the make-or-break factor. 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 instead of running straight. Aim for a pH of 6.0 to 7.0.
Temperature
They're hardy and grow across a wide range, roughly 36°F to 75°F (2°C to 24°C). The roots happily take frost in the ground, and that cold is exactly what sweetens them.
Humidity
Ordinary outdoor air suits them, somewhere around 40% to 70%, and there's nothing to manage on this front. The soil moisture is what counts.
Feeding
Go light. Feed once at sowing and again mid-season with a balanced, low-nitrogen fertilizer, because too much nitrogen or any fresh manure pushes forked, hairy roots instead of clean ones.
Pruning
Parsnips need no real pruning. Thin the seedlings to 3 to 4 inches apart once the true leaves show so the roots have room to size up, and cut off any flower stalk that tries to bolt in the first year.
Size & spacing
The leafy tops stand about 12 to 18 inches (30 to 45 cm) tall and spread 8 to 12 inches (20 to 30 cm). Thin plants to 3 to 4 inches apart in the row so each root has space to swell.
When to plant
Parsnips run on a slow clock. Direct sow in early spring, a few weeks before the last frost, once the soil is workable and at least 40°F (4°C), then leave them to size up all season. Wait to harvest until late fall and through winter, since a hard frost is what makes the roots 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 parsnip problems happen out of sight, either at sowing or down in the root. A blank row or a misshapen root usually traces back to the seed, the soil, or the weather. Match what you find below, then fix the cause before next season.
Patchy or no seedlings after weeks of waiting
Parsnip seed is short-lived, so old or carried-over seed is the usual reason a row never comes up. The seeds also need 14 to 28 days and a seedbed that never dries out, since a crusted surface stops them cold. Sow fresh seed each spring, keep the bed damp until the seedlings show, and tuck in a few fast radishes to mark where the row is.
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
Roots that fork, split, or grow whiskery
A clean parsnip needs a clear run straight down, so stones, clods, and heavy soil are what make the taproot split and branch. Fresh manure or too much nitrogen pushes the same hairy, forked growth, and so does disturbing the root by transplanting. Dig the bed deep and pull out the rocks before sowing, feed only with low-nitrogen amendments, and always direct sow.
Fix:
- Cultivate and de-stone soil deeply before sowing
- Use low-nitrogen, well-rotted amendments only
- Direct sow rather than transplant
Dark, sunken rot at the root shoulders
This is canker, a fungal rot that takes hold in wet, poorly drained soil and gets in through cracks or injuries at the crown. Wet seasons make it worse. Improve the drainage, hill a little soil 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'
Rusty tunnels boring through the roots
Those rust-colored trails are the work of carrot rust fly larvae, which mine the lower root while the adult flies work the foliage in spring and late summer. Drape the rows with floating row cover to keep the flies off, move the bed away from last year's carrots and parsnips, and hold off sowing until the early flight has passed.
Fix:
- Cover rows with floating row cover
- Rotate away from previous carrot/parsnip beds
- Delay sowing to avoid peak fly flights
Toxicity
The parsnip you eat is a safe, wholesome root once it's peeled and cooked, and a stray nibble won't harm a pet. The hazard lives in the foliage and sap, which carry furanocoumarins that can burn skin in sunlight, so handle the tops with gloves and keep animals from grazing the leaves 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 curious nibble of root is no real worry. The bigger risk is the sap on the foliage, which can irritate the mouth or thin-furred skin, so keep a cat away from the tops.
Dogs Mild
Parsnip isn't on the ASPCA toxic list for dogs, and the cooked root is harmless. A dog that chews the leaves may pick up some mouth irritation from the sap, and any sap on bare skin can sting in sunlight, so the foliage is worth keeping out of reach.
Horses Mild
Horses graze parsnip tops without much trouble, but the furanocoumarins in the foliage can leave pale, thin-skinned areas like the muzzle sore once the sun hits them. Watch for any irritation or peeling on bare skin after they've been in the patch.
Rabbits Mild
A little parsnip is a fine treat for a rabbit, and the root causes no harm. Go easy on the leafy tops, since the sap can irritate, and hand over only small amounts at a time.
Livestock Mild
Cattle, goats, and sheep can eat parsnip foliage, though the same sun-triggered compounds may redden or blister pale, exposed skin around the face. Heavy grazing of the green tops is the part to limit.
Birds Mild
Backyard hens peck at parsnip root and scraps without any problem. The foliage carries the irritant sap, so it's best not to pile fresh tops into the run.
People Root safe, sap a hazard
The peeled, cooked root is a sweet, wholesome vegetable that's safe to eat. The real danger is the sap on the leaves and stems, which contains furanocoumarins that trigger phytophotodermatitis, a painful sunlight-driven rash with blisters and lingering brown marks. 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 root shape, sweetness, and how well they fend off canker. These are the ones you'll meet most often.
Hollow Crown
A long-rooted heirloom with broad shoulders and a sunken crown that rewards you only in deep, stone-free soil it can drive straight down through.
Harris Model
A favorite home-garden type prized for smooth, uniform white roots with a fine texture and reliably sweet flavor.
Gladiator F1
A vigorous hybrid that shrugs off canker far better than most while still turning out smooth, even white roots.
Cobham Improved Marrow
A sweet, canker-tolerant variety with clean-skinned, 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's only one way to start a parsnip, and that's from seed sown right where it 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
Parsnips grow from seed sown straight into the ground, since the taproot won't tolerate being moved. Buy fresh seed every year, because it loses its punch fast, and sow in early spring once the soil is workable. Then comes the test of patience: the seed can take 14 to 28 days to germinate, so keep the bed evenly moist the whole time, and the roots are ready to lift about 100 to 130 days later.
Myths
Parsnips are just white carrots.
They look related, but parsnip and carrot are different species, Pastinaca sativa and Daucus carota. Parsnip is sweeter and starchier, with a flavor that turns richer after a frost.
Parsnip leaves are safe to handle like any other garden green.
The leaves and sap hold furanocoumarins, and once they touch your skin and meet sunlight they cause phytophotodermatitis, a blistering chemical burn. Always 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.
You can eat them any time, frost or no frost. Cold weather simply turns some of the starch into sugar, so frosted roots taste sweeter rather than only then becoming safe.