Parsnips have a reputation for being difficult, and almost all of it comes down to one stage: getting the seed to come up. Once a row of parsnips (Pastinaca sativa) is established, it is one of the least demanding crops in the garden — no staking, no feeding, hardly any pests — and it ends the year as a winter larder you can dig from November to February. The trick is in three decisions you make before you sow: fresh seed, the right soil, and the right moment. This guide covers all three, then takes you through thinning, watering and the problems worth knowing about, so next spring's sowing is the one that works.
- Sow Outdoors, late March–May · best once the soil reaches about 7–8 °C
- Germination Slow and patchy · 2–4 weeks · always use fresh seed
- Spacing Thin to 15–20 cm · rows 30–40 cm apart
- Harvest October–February · sweetest after the first hard frosts
What kind of plant is a parsnip?
The parsnip is a member of the carrot family, the Apiaceae, and a close relative of carrots, celery and parsley. Botanically it is a biennial: in its first year it builds a long, starchy taproot, and if left in the ground it uses that store in the second spring to send up a tall flowering stem with flat yellow umbels. In the vegetable garden we treat it as an annual and lift the root before that happens. That is why seed packets — including ours — often describe parsnips as annual: it is how they are grown, not how they live.
The variety we stock is 'Guernsey', an old Channel Islands parsnip with a demi-long, tapered root rather than an extremely long one. That shape is a practical advantage: it copes better with ordinary garden soil than the long exhibition types, which need very deep, perfectly prepared beds. You will find it in the parsnip seed collection, which is also listed under the botanical name Pastinaca sativa, and in certified organic form.
Why parsnip seed fails — and how to stop it
Most failed parsnip rows have the same three causes.
- Old seed. Parsnip seed is among the shortest-lived of all vegetable seeds. It is thin, papery and loses viability quickly; a packet that sat in a warm kitchen drawer for a year can give almost nothing. Buy fresh seed every spring and store it cool and dry until sowing day — our guide to how long seeds last explains why some seeds keep for years and parsnips don't.
- Cold, wet soil. The old advice to sow in February comes from a time of long-lasting seed and patient gardeners. In cold soil the seed sits for weeks and often rots. Sowing a little later, from late March in mild areas and April–May elsewhere, gives quicker, more even germination — and later sowings are also less prone to canker. Our seed is tagged for April sowing for exactly that reason.
- A crust on the surface. Seedlings of parsnip are weak pushers. Heavy rain followed by sun forms a crust they cannot break. Cover the seed with fine compost or sieved soil rather than clay, and keep the surface moist until they are up. If a row stays bare, our guide to why seeds aren't germinating helps you find the cause.
Preparing the bed
A parsnip root grows straight down. Anything in its way — a stone, a lump of clay, a pocket of fresh manure — makes it fork or twist. Choose an open, sunny spot and dig or loosen the soil to a spade's depth, removing stones as you go. Do not add fresh manure: rich, freshly manured soil is a classic cause of forked, hairy roots. The ideal bed is one that was manured for a previous crop, which is why parsnips sit in the roots bed of a four-bed crop rotation, after the brassicas or legumes. On heavy clay, a raised bed or a deeply loosened strip with added sharp sand and old compost works well. More on that in how to prepare your soil.
How to sow parsnips, step by step
Parsnips are always sown where they are to grow: the taproot does not like being moved. If you are new to sowing outdoors, our guide to direct sowing in the garden covers the basics.
- Check the soil, not the calendar Wait for a dry spell when the soil crumbles in your hand and has started to warm — usually April. Rake it to a fine, level tilth.
- Make a shallow drill About 1–2 cm deep, with 30–40 cm between rows. Water the drill before sowing, not after, so the seed isn't washed out.
- Station-sow in threes Drop two or three seeds every 15–20 cm rather than sowing a continuous line. It wastes less seed and makes thinning easy.
- Mark the row with radishes Sprinkle a few radish seeds between the stations. They come up in days, show you where the row is for weeding, and are eaten long before the parsnips need the space — see how to grow radishes.
- Cover with fine compost and keep moist Fill the drill with sieved soil or seed compost, firm lightly, and water gently in dry weather until the seedlings appear in two to four weeks.
- Thin to one per station When the seedlings have their first true leaves, snip off the weakest at soil level, leaving the strongest every 15–20 cm.
A useful trick for stubborn soils: pre-germinate the seed. Spread it on damp kitchen paper in a closed container at room temperature and check daily. As soon as the first tiny roots appear, sow the seeds carefully into the drill. You lose the waiting time and know that every station has a live seed.
Looking after the crop
Once the seedlings are up, parsnips need very little.
- Weed early. Seedlings are slow and fine-leaved, and weeds overtake them easily in May and June. Hoe carefully between rows; after midsummer the parsnip leaves shade out most weeds on their own. A light mulch helps — see mulching and weed control.
- Water evenly. In a long dry spell, a thorough soak every week or two is better than frequent sprinkling. A sudden downpour after drought makes the roots split.
- Do not feed. Extra nitrogen produces leaves, not roots. A bed that was manured the previous year has all a parsnip needs.
- Wear gloves for the foliage. Parsnip sap contains compounds that can cause skin blisters when the skin is exposed to sunlight. Wear gloves and long sleeves when weeding among the leaves on sunny days.
Parsnip or carrot: same family, different habits
Parsnip
One long sowing, one long season, harvested all winter.
- Sow once, March–May; ready from October
- Seed is short-lived: buy fresh each year
- Stays in the ground through winter and sweetens with frost
Carrot
Several sowings, quicker crops, more pest pressure.
- Sow in succession from March to July
- Seed keeps for about three years
- Carrot fly is the main pest — see the carrot guide
Harvesting and storing
From a spring sowing, the roots are usable from October, when the foliage starts to yellow and die back. There is no hurry: parsnips are fully hardy, and after two or three hard frosts part of their starch turns to sugar, which is why the best roots come in December. Lift them with a fork as you need them, never by pulling the leaves. Our spoke guide on when to harvest parsnips covers the signs of readiness, lifting step by step and mulching the row so you can dig in a freeze. For heavy, wet soil where the roots are better out of the ground, see how to store root vegetables over winter in boxes of damp sand.
Common mistakes
- Sowing last year's seed — the single biggest cause of an empty row. Start with a fresh packet every spring.
- Sowing too early into cold soil — seed rots before it germinates. April usually beats February.
- Adding fresh manure — roots fork and grow hairy. Use a bed manured the year before.
- Transplanting seedlings — the taproot is damaged and the root forks or stops. Always sow in place.
- Giving up too soon — two to four weeks is normal. Don't dig the row over after ten days.
- Ignoring canker — orange-brown patches on the shoulders. Sow a little later, keep the roots covered with soil and rotate the bed each year; see common garden pests and problems.
Frequently asked questions
When should I sow parsnip seeds?
Outdoors from late March to May, once the soil has dried out and started to warm. In most gardens April is the most reliable month. Early sowings are not faster — they often just sit in cold soil.
Why do parsnips take so long to germinate?
Parsnip seed germinates slowly even in good conditions, typically in two to four weeks, and much more slowly in cold soil. Old seed makes it worse. Pre-germinating on damp kitchen paper is the most reliable way to speed things up.
Can I grow parsnips in containers?
Yes, if the container is deep — at least 40 cm — and filled with a light, stone-free compost mixed with sand. A demi-long variety such as 'Guernsey' suits containers better than long exhibition types.
Can I save my own parsnip seed?
Yes. Leave a few of the best roots in the ground over winter; they flower in their second summer and set plenty of seed. Because parsnip seed is so short-lived, sow it the following spring. Our seed saving guide covers drying and storing umbellifer seed.
A single April sowing of parsnips, done well, gives you roast roots from the first frosts until February — with almost no work in between. If you are new to vegetables, start with our beginner's guide to growing vegetables from seed. Browse all our root vegetable seeds, carrots and vegetable seeds, see all our seeds, or explore the rest of our growing guides.
