Parsnips are the slowest crop in the vegetable garden and the most patient in return. Sown in spring, they spend the whole summer quietly building a long, pale root — and then they wait for you, in the ground, right through the winter. The question most growers ask in October is not how to grow them but when to dig them up. The short answer: you can start lifting as soon as the roots are a good size, but parsnips are at their best after the first proper frosts, and the row in the ground is the best store you have. This guide explains how to tell when parsnips are ready, why frost makes them sweeter, how to lift them without snapping them, and how to keep a supply coming until spring.
- Ready From October · 16–20 weeks after sowing, when the leaves start to yellow and die back
- Best flavour After two or three hard frosts · cold turns stored starch into sugar
- Harvest window October–February, lifted as needed · finish before new growth in March
- How Loosen with a fork alongside the row · lift, never pull by the leaves · don't wash roots you store
How to tell when parsnips are ready
Parsnips (Pastinaca sativa) need a long season: from a spring sowing, the roots are usually usable from about 16 weeks and fully grown at 18–20. In practice that means a March–May sowing is ready from October. There are three signs to look for:
- The foliage dies back. As autumn cools, the leaves yellow and collapse. That is the plant shifting its energy into the root, not a sign of trouble.
- The shoulders are broad. Scrape a little soil away from the top of a root. A shoulder of 4–6 cm across means a full-sized parsnip below; smaller is fine to eat, just less of it.
- A test root looks right. Lift one from the end of the row. If it is long, pale and firm, the row is ready whenever you want it.
Parsnips belong to the same family as carrots and need the same deep, stone-free soil — our guide to growing carrots from seed covers the soil preparation both crops share.
Why frost makes parsnips sweeter
A parsnip lifted in early October is perfectly edible but rather starchy. Once the roots have been through a couple of frosts, they taste noticeably sweeter and nuttier. This is not folklore: when temperatures drop close to freezing, the root converts part of its stored starch into sugars, which act as a natural antifreeze for the plant's cells. For the gardener it means the best parsnips of the year come in late November and December — which is why they are such a traditional winter roast vegetable.
So unless you need the space, there is no hurry. Lift a few early ones if you want them, but leave most of the row to sweeten.
How to lift parsnips, step by step
- Pick a day when the ground isn't frozen Frosty air is fine; frozen soil is not. Roots dug from frozen ground snap and bruise, and you will damage the soil structure too.
- Cut back or twist off the old foliage Clearing the dead leaves first shows you exactly where each root sits. Wear gloves if the foliage is still green: parsnip sap can irritate skin in sunlight.
- Loosen the soil alongside, not on top Push a garden fork in vertically 10–15 cm from the row and lever it back gently, working along the row. Parsnip roots can reach 30 cm or more, so go deep.
- Ease the root out Grip the root at the crown and lift as you loosen. Never yank the leaves: they tear off and leave the root behind, often broken.
- Trim and sort Twist off the remaining leaves, leaving a short stub. Knock off loose soil but don't wash roots you plan to keep. Use any damaged, forked or cankered roots first.
- Re-firm the row Push the soil back around the remaining parsnips so the exposed roots don't freeze or attract pests.
Keeping parsnips through the winter
The row itself is the easiest store. Parsnips are fully hardy and keep in good condition in the soil until late winter. The one problem is a hard freeze, when the ground becomes impossible to dig for days at a time. Two simple tricks solve it:
- Mulch the row. In November, cover the row with 15–20 cm of straw, bracken or leaf mould, held down with netting or a plank. The soil underneath stays workable in all but the hardest frosts.
- Lift a frost reserve. When a cold spell is forecast, dig a week or two's worth and keep them in a box of damp sand in a cool shed or garage.
On heavy, waterlogged soil or where slugs and carrot fly are a problem, it may be better to lift the whole crop in December and store it. Either way, finish by the end of February: as the days lengthen, parsnips start to regrow, and the roots turn woody as the plant puts its energy into a flowering stem. For the full winter plan for the veg patch, see putting the vegetable garden to bed.
Leave in the ground or lift and store?
Leave in the ground
The traditional method on free-draining soil.
- Best flavour: roots keep sweetening with each frost
- No storage space or work needed
- Needs a mulch so you can dig in a freeze
Lift and store in sand
For heavy, wet soil or when the bed is needed.
- Always accessible, whatever the weather
- Keeps 2–3 months at 0–4 °C in damp sand
- Lift after the first frosts to keep the sweetness
Common mistakes
- Lifting the whole row in October — you miss the frost-sweetened flavour. Dig as needed instead.
- Pulling by the leaves — the tops snap off and the root stays in the ground. Always loosen with a fork first.
- Digging frozen soil — roots break and bruise. Mulch the row before the cold arrives.
- Washing roots before storage — wet skins rot. Brush off soil and store them dirty.
- Leaving them too long — roots that start regrowing in March turn woody and bitter.
- Ignoring canker — orange-brown or black patches on the shoulders spread in store. Use those roots first.
Frequently asked questions
Do parsnips need frost before harvesting?
No, they are edible as soon as they are big enough. But they taste noticeably sweeter after two or three frosts, because the cold converts starch into sugar. Most growers start lifting in November for that reason.
Can you leave parsnips in the ground too long?
Yes. They keep well through winter, but once growth restarts in late February or March the roots become woody as the plant prepares to flower. Aim to lift the last of the row by the end of February.
Why are my parsnips forked or stunted?
Forking is caused by stones, compacted soil or fresh manure in the bed; stunted roots usually mean the seed was sown late or in poor, dry soil. Next year, sow into deep, well-dug ground that was manured for a previous crop — our guide to crop rotation shows where parsnips fit.
When should I sow parsnips for next winter?
Sow outdoors from March to May, once the soil has warmed a little, and always use fresh seed: parsnip seed loses its viability within a year or two. Germination is slow, often three to four weeks, so mark the rows with a few radishes.
A row of parsnips sown in spring is a winter larder you never have to fill: lift a few at a time after the frosts and they will keep you in roast roots until February. October is also a fine month to sow hardy perennials in pots outside — coneflowers, for instance, germinate after a winter outdoors. Browse the Pastinaca sativa and organic parsnip collections, the wider root vegetables and vegetable seeds, everything to sow in April, or all our seeds, and keep our growing guides to hand for the season ahead.
