Top 5 Crops to Harvest Through a Scottish Winter

Hardy crops do not simply put up with cold. As autumn days shorten, they harden, accumulating sugars and amino acids that act as anti-freeze in their tissues. That is why a frosted parsnip tastes sweeter than one lifted in September, and why a sprout stalk can stand through a hard January and still be worth picking. The plant is doing work on your behalf, but only inside limits.

Why hardy crops cope, and where it stops

The protection has to be built before the freeze. Plants need several days of cold to harden, so even a hardy crop can be damaged by a sudden frost in October before it has adjusted. For a grower, this means autumn matters. A cabbage that has slid gradually into cold is tougher than the same plant caught by one freak night.

Three things break the system.

Frost damage itself. Acclimatisation has a ceiling, and wind makes frost damage worse. An exposed, gale-scoured plot punishes a crop far more than a sheltered one at the same temperature, so where you site winter crops matters as much as which ones you choose. Our guide to frost pockets and suntraps covers how cold air pools on your own plot, and protecting plants from frost covers what to do when a hard night is forecast.

Waterlogging. Saturated soil has its air pushed out from between the particles. Root function is reduced or stops, the roots start to die, and rots move in. There is one mercy: in cold winter soil, roots and soil microorganisms respire very little, so waterlogging does far less harm than the same sogginess in summer. A wet November does not automatically finish a crop. But a plot that stays under water for weeks is a real risk, and in wetter parts such as the Glasgow area it can be a bigger threat than the cold. Our piece on flooded plots and drainage covers the fixes.

Light. Hardy crops hold in winter, they do not grow. Leeks keep growing slowly through the season; others stall entirely, and chard stops producing new leaves once temperatures drop. Scottish winter light is thin: Lerwick averages roughly 21 hours of sunshine across the whole of December, and about 42 at Bishopton near Glasgow. Whatever size a crop reached by late autumn is essentially the harvest you will get, so sow and plant to finish growing before the light goes. The day-length article and the piece on growing through winter darkness in Shetland and Orkney explain the mechanics.

Heavy snow can flatten tall brassicasThe cabbage family: cabbage, kale, broccoli, cauliflower, Brussels sprouts, kohlrabi, swede, turnip and more, sharing the same pests, diseases and rotation rules. Full definition → and collapse netting on hoops, so stake plants and use firm supports.

The five picks

1. Kale

Kale is one of the hardiest leafy vegetables you can grow, and it is a safe first choice for a Scottish winter plot. It is ready from September onwards and gives plentiful pickings through autumn, winter and spring. You take two or three lower leaves per plant at a time, so the plant keeps working for you rather than being cut down in one go. It prefers rich, well-drained, firm soil. Because you are eating leaves rather than something buried in cold mud, it copes with a wet winter better than the root crops on this list.

Its weaknesses are wind and pigeons. Tall varieties in exposed spots need sturdy canes, because winter gales can rock the plants and loosen the roots. Pigeons peck at the leaves and tear them, and in a cold spell, when there is little else on offer, they can do serious damage. Fine-mesh netting on hoops or canes is the answer (more on pigeons below). Sowing and spacing are in the kale guide, and varieties are in best kale varieties for Scotland.

2. Leeks

Established leeks need no frost protection, and late varieties can stay in the ground through winter and into spring, harvested whenever you want them. Frost may even sweeten the flavour. They can look sick after a sharp frost, then rebound and carry on growing slowly. A full-sized leek takes up to six months from sowing, which is why leeks are the classic filler for ground that would otherwise sit empty over winter.

They want a sunny spot with free-drainingSoil that lets water pass through quickly rather than pooling, so roots aren't sitting in wet ground after rain. Full definition → soil, and that is the honest catch for a wet plot. A leek bed on sticky clay that holds water through December is where you will get a poor, hard-to-lift crop, and leeks are far less forgiving of that than kale. A raised bed sorts it out. Leek moth, allium leaf miner and onion fly are the growing-season pests to plan for, and if rust (orange pustules on the leaves) has hit your plot before, choose resistant varieties. See the leek guide and best leek varieties for Scotland.

3. Parsnips

Parsnip roots are very hardy and can be left in the ground into winter and dug as needed. Wait until after the first heavy frost before lifting, since it intensifies their sweetness and flavour. They take around four to six months from sowing, and the seed wants soil at roughly 12°C, which comes late in a Scottish spring. That long run then has to finish before the thin December light described above, so a patient April sowing beats an impatient March one.

The trouble is access. Parsnips can be difficult to lift from frozen ground, so lift a few extra in November as a safety stock. A 15-20cm layer of straw over the row keeps the ground from freezing solid and keeps digging possible. The soil matters too: take out stones and loosen heavy clay or compacted ground to avoid forked roots, and skip fresh organic matter just before sowing. Canker, an orange-brown rot, is worth planning around by choosing a resistant variety such as Albion or Picador. See the parsnip guide and best parsnip varieties for Scotland.

4. Brussels sprouts

Brussels sprouts can withstand harsh winter weather where they stand. Early varieties crop from autumn, but the main season is winter, and the sprouts are sweeter once frosted. Start picking from the bottom of the stalk when the sprouts are walnut-sized, firm and still tightly closed, taking the lower leaves off as you go. Pick before they open or turn yellow.

They are the most demanding of the five. The plants are tall and top-heavy, so in late summer mound soil around the stem bases, give them firm ground, and stake tall varieties in exposed spots before the autumn gales arrive. Pigeons are a serious problem, and the easiest fix is insect-proof mesh on canes, pinned into the ground. Lime the winter before sowing to raise the pH to at least 6.5 and deter clubroot, and rotate brassicasMoving each crop family to different ground each year, on a multi-year cycle, so pests and diseases that build up in soil don't get a repeat host. Full definition → onto fresh ground. ClubrootA soil-borne fungal disease of the brassica family that swells and distorts roots, and survives in soil for years. Full definition → is a soil disease that swells and distorts brassica roots, and it is a risk shared with kale and cabbage. The Brussels sprout guide has the calendar and best Brussels sprout varieties for Scotland covers what to grow.

5. Winter cabbage

Savoy and January King types are bred for the cold. Once mature they often stand in good condition for months until you need them, and the hardy winter types are remarkably tough, shrugging off frost. They fill the gap between the sprouts and the first spring greens. Cut through the stem just above ground level with a sharp knife, then dig out the stumps afterwards to deter the spread of brassica diseases.

They share the pests of kale and sprouts. Cabbage butterflies (cabbage white caterpillars), root fly, whitefly and pigeons all go for them, and fine-mesh netting covers every one. Firm ground and lime against clubroot set them up well; the same liming applies to kale. Sowing windows are in the cabbage guide, and varieties are in best cabbage varieties for Scotland.

How the five compare

When to sow and plant

Every one of these is a spring or early-summer sowing, so plan a year ahead. If you are starting late, buy young plants.

In colder or later parts of Scotland, aim for the later end of each window. For parsnips, 12°C soil means April or later in most places, and March only in the mildest plots.

What else to plan for

When the ground is frozen solid

Frozen soil is the practical enemy of root crops. Cover the parsnip row with straw as described above, and lift a few extra roots in November so you are not stuck. Roots that are already lifted keep best cool and out of the frost; root cellars and cool storage and storing carrots for winter cover the options.

When the ground is a bog

Sodden ground needs different tactics. Raised beds put the roots above the surrounding water, and they are the most realistic answer for a plot that stays wet; flooded plot drainage sets out the order to try things in. Give the best-drained bed to the roots and let kale take the heavier ground. If a plot has actually flooded, root crops and raw vegetables that the water has touched should be discarded.

Pigeons, rabbits and deer

Winter is when pigeons get bold, and brassicas are what they want. Covering the crop is one of the most effective deterrents, so use fine mesh on hoops or canes, held clear of the leaves. Rabbits and deer will eat kale and sprouts as readily, and bird netting does not stop them. Fencing and barriers are covered in keeping rabbits out, keeping deer out and keeping your crops safe.

Mud and access

A winter plot needs paths you can stand on. Lay boards or stepping stones between the rows before the wet weather sets in, so you are not trampling and compacting the soil around the roots every time you pick a leaf.

In a hard freeze

FleeceA lightweight, breathable fabric laid or draped over plants to trap a little warmth and keep off frost, wind and some flying pests. Full definition → over kale and cabbage takes the edge off a hard night, and garden fleece grades and timing covers which weight to buy. A cold frame is a good home for any late chard you want protected.

Regional notes

Four stations, Met Office 1991-2020 averages:

Frost days are similar in the Borders and around Glasgow, but Bishopton gets nearly three times the rain, so on the wetter ground around Glasgow waterlogging outweighs frozen soil. Higher ground will usually be colder than any of these stations, so lean toward kale and winter cabbage over parsnips you may not be able to dig. Frost timing for your own area is on the frost dates page.

Other crops that overwinter in the ground

Celeriac is extremely hardy and can stay in the ground right through to spring, harvested October to March. It needs a long season from an early heated sowing, wants consistently damp soil while still hating waterlogging, and slugs tunnel into the roots. In colder regions, spread straw round it so the soil does not freeze. See storing celeriac for winter and best celeriac varieties for Scotland.

Swede can be left in the ground into winter, but where the soil sits wet over winter, or in cold regions, the advice is to lift in late autumn and store. Even hardy swedes do best covered with straw, clochesA small, portable clear cover placed over an individual plant or short row to trap warmth and keep off wind, rain and pests. Full definition → or fleece before winter. See storing swede and turnip and best swede varieties for Scotland.

Chard survives winter outdoors without protection but stops producing new leaves once temperatures drop. Cloches keep a few leaves coming in mild spells and bring on spring growth, and a July sowing gives leaves the following spring. See best chard varieties for Scotland.

Sprouting broccoli shrugs off hard weather and is a good late-winter option. If you are new to growing, the low-maintenance beginner crops are a gentler start.

Common questions

Sources