Crop guide · The carrot and parsley family

How to grow parsnips

A slow-growing root vegetable whose starch converts to sugar after hard frost, producing a sweet, nutty flavor unmatched by any summer harvest.

Pastinaca sativa · also called white carrot, hollow crown

Full sun Intermediate Frost-hardy
Sun
Full sun
Afternoon shade helps where summer temperatures regularly exceed 85 °F (29 °C) during the long growing period.
Frost
Hardy
Survives hard frost and even frozen ground
Spacing
4 in
10 cm between plants
Sow depth
½ in
13 mm
To harvest
100–130 days
counted from sowing
Soil pH
5.5–7.0
on the acidic side
Timing

When to plant parsnips

Windows are counted from the average date of your last spring frost.

Summer:12–14 weeks before first fall frost for an overwintered crop.
Too late?Skip a spring sowing once soil tops 70 °F (21 °C) consistently — germination fails; switch to a late-summer sowing for fall harvest instead.
Background

Why grow parsnips

Home-grown parsnips left in the ground through autumn frosts develop a depth of sweetness that store-bought roots — harvested before cold sets in — rarely achieve. They also occupy bed space during the shoulder seasons when little else is growing.

A little history. Native to Eurasia and documented in cultivation since antiquity; seed viability drops sharply after one year, making fresh seed essential for reliable germination.

The season, step by step

From planting to harvest

Sow outside

2–4 weeks before last frost

Sow seeds ½ inch (13 mm) deep, and aim for 4 inches (10 cm) between plants once thinned. Keep the top inch consistently moist; sow shallowly and lay a board or damp burlap over the row to hold moisture, removing it the moment sprouts appear. Seedlings emerge in 14–28 days.

Best soil temp 55–65 °F (13–18 °C) Minimum 50 °F (10 °C) Emerges in 14–28 days

Water and feed

All season

Water deeply once or twice a week; reduce frequency once roots are established but never let soil dry out completely. Water when the top 2 inches of soil feel dry to the touch. Aim for about 1 inch per week including rain.

Side-dress (scatter fertilizer along the row and water in) once at 6 weeks after germination; avoid heavy feeding after that. What to use: low-nitrogen, higher-phosphorus and potassium feed such as a 3–6-6 organic blend; excess nitrogen drives leafy top growth at the expense of root development.

Harvest and store

100–130 days from sowing

It's ready when roots are 1–2 inches across at the shoulder and at least 8 inches long; flavor peaks after two or three hard frosts have chilled the bed. Loosen the soil 6 inches away from the root with a fork, pressing down rather than levering, then pull the root straight up by the base of the foliage to avoid snapping the taproot.

Leave roots in the ground under straw mulch until needed — they keep best in situ. Lifted roots store up to 4 months in a cool, humid place (32–35 °F (0–2 °C)) packed in barely damp sand.

Companions

Good neighbours, bad neighbours

Plant it with

Garlic

Carrot fly finds its host by smell, and a row of garlic alongside can help muddle that trail during the weeks parsnip foliage is most attractive. Useful under low pest pressure, but it is no substitute for fine mesh over the bed.

Onion

The sharp smell of onion foliage often reduces how readily carrot fly homes in on nearby carrot-family roots. The effect fades once the onions are pulled, so plan mesh cover for the long tail of the parsnip season.

Radish

Radish sprouts in days and marks the row while parsnip takes two to four weeks to appear, and its shallow roots keep the surface crust broken. Pull the radishes within a month, long before parsnip taproots reach for depth.

Garden Pea

Peas bank nitrogen in root nodules, but most of it becomes available only as those roots break down, so the benefit lands on the following season rather than the standing parsnip crop. Cut peas at soil level and leave the roots in place.

Lettuce

A low band of lettuce shades the seedbed and holds moisture during the slow parsnip germination, and it crowds out weeds that would otherwise get a head start. Harvest the lettuce before parsnip leaves close over the row.

Keep it away from

Carrot

Both are carrot-family roots and share carrot fly plus the soil fungi behind canker and violet root rot, so planting them side by side concentrates the problem and makes rotation harder. Keep them in separate beds and separate years.

Celery

Celery belongs to the same family and hosts the same leaf miner and carrot fly, so a mixed planting often keeps both pests running through the bed all season. Its heavy watering needs also favor the fungi that rot parsnip shoulders.

Dill

Dill is a fast, tall carrot-family plant that shades young parsnip leaves and self-sows freely through the row, and it carries the same pests. The two are separate species and cannot cross; the real conflict is crowding and shared insects.

Skirret

Parsnip shares skirret's family and its troubles: carrot fly, and the soil-borne root rots that linger for years. Growing them in one bed stacks the pressure and leaves you nowhere clean to move either crop.

See parsnips in the full companion chart →

Crop rotation

After this crop

Family rest

Give the carrot family 3 years away from this spot before any of its relatives return.

Good next crops

The pea and bean family, the cabbage family or the onion family thrive in this ground next season.

Parsnip is a light feeder that leaves the bed loose and open, its taproot breaking up compacted subsoil down to a foot or more. Keep all carrot-family crops out of this ground for 3 years. Follow with legumes to rebuild nitrogen, then brassicas or an onion-family crop.

Trouble to watch for

Pests and diseases

Pests

Carrot fly

Sign
Rusty-brown tunnels just under the root skin; foliage yellows and wilts from the top down.
Fix
Cover the bed with fine insect-proof mesh from sowing to harvest; no effective organic spray once larvae are inside the root.

Celery leaf miner

Sign
Pale, blister-like tunnels winding through the leaves; heavily mined leaves turn brown and papery.
Fix
Pick off and destroy affected leaves promptly; cover young plants with mesh to prevent adult flies from laying eggs.

Aphids

Sign
Clusters of small soft insects on leaf undersides and growing tips; leaves curl or pucker.
Fix
Knock off with a firm jet of water; repeat daily for a week. Introduce or encourage natural predators such as ladybirds.

Slugs

Sign
Irregular surface gouges on the crown and upper root; slime trails visible in the morning.
Fix
Apply iron phosphate pellets around the row at dusk; remove any mulch touching the crown.

Diseases

Parsnip canker

Sign
Orange-brown to black rotted patches at the shoulder (top) of the root, often with cracked, sunken tissue.
Prevent
Grow a canker-resistant variety; avoid damaging roots when thinning; ensure good drainage and do not over-apply nitrogen.

Powdery mildew

Sign
White powdery coating on upper leaf surfaces, first appearing as discrete circular patches that merge.
Prevent
Space plants to the full 4-inch recommendation to allow airflow; water at the base, not overhead; remove affected leaves promptly.

Violet root rot

Sign
Purple-violet fungal threads matting the root surface; roots rot from the outside in; foliage yellows and collapses.
Prevent
Rotate root crops on a minimum 4-year cycle; improve drainage; avoid waterlogged soil, which favors the fungus.
Good to know:The foliage and seed contain compounds that cause phototoxic skin burns (blistering on contact with sap in sunlight); handle plants with gloves and long sleeves, especially when thinning or harvesting in sun.
FAQ

Common questions about parsnips

When should I plant parsnips?
Spring: 2–4 weeks before last frost, once soil reaches 50 °F (10 °C). Summer: 12–14 weeks before first fall frost for an overwintered crop.
How long until parsnips are ready to harvest?
100–130 days, counted from sowing. It's ready when roots are 1–2 inches across at the shoulder and at least 8 inches long; flavor peaks after two or three hard frosts have chilled the bed.
Can I grow parsnips in a container?
Deep garden bed strongly preferred; roots reach 10–18 inches and will fork in shallow or stony soil. In containers: 15-gallon deep pot or half-barrel, minimum 18 inches deep.
How often should I water parsnips?
Water deeply once or twice a week; reduce frequency once roots are established but never let soil dry out completely. Water when the top 2 inches of soil feel dry to the touch.
Is any part of parsnips unsafe to eat?
The foliage and seed contain compounds that cause phototoxic skin burns (blistering on contact with sap in sunlight); handle plants with gloves and long sleeves, especially when thinning or harvesting in sun.
How should I store parsnips after harvest?
Leave roots in the ground under straw mulch until needed — they keep best in situ. Lifted roots store up to 4 months in a cool, humid place (32–35 °F (0–2 °C)) packed in barely damp sand.

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