How to Grow Swedes

Swedes are proper workhorses in the vegetable garden, tolerating our unpredictable weather better than most crops whilst improving the soil for whatever follows them. Whether you’re working with heavy clay in the Midlands or sandy loam in East Anglia, swedes will adapt, provided you give them the right start and avoid a few common pitfalls that catch out many first-time growers.

How to Grow Swedes

Before you start sowing, it’s worth gathering everything you’ll need. I’ve found that having the right materials on hand makes the whole process smoother, particularly when you’re dealing with direct sowing outdoors.

Essential Materials

For the basic growing process, you’ll need swede seeds (obviously), a well-prepared bed with neutral to slightly alkaline soil (pH 6.0 to 7.5 works brilliantly), and a decent rake for creating a fine tilth. I always keep a garden line handy for marking straight rows, though this is more about organisation than necessity. You’ll also want some organic matter like well-rotted compost or manure to dig in several weeks before sowing, as swedes are hungry feeders. A hoe becomes essential once seedlings emerge, as you’ll be doing regular weeding to prevent competition. Don’t forget fleece or fine mesh netting, which I consider absolutely essential for protecting young plants from flea beetles and cabbage root fly. Love tomatoes? You may like the article your complete tomato growing guide.

Optional But Helpful Items

A soil testing kit helps you check your pH levels, particularly important if you’ve had problems with clubroot in the past. I use a dibber for thinning out seedlings, though your fingers work just as well. Cloches can extend the season at both ends if you’re in a colder region like Scotland or the North East. A watering can with a rose attachment gives you better control during dry spells, and labels help you remember which variety you’ve planted if you’re trialling different types. Some growers swear by collars made from carpet underlay or cardboard to deter cabbage root fly, though I’ve found that mesh does the job just as well without creating waste.

Step-by-Step Instructions

Preparing Your Soil

Start your preparation at least three to four weeks before sowing. Swedes prefer a firm, fertile bed, so if you’re working with newly dug ground, you’ll need to let it settle. I dig in plenty of well-rotted organic matter during late winter or early spring, but avoid fresh manure which can cause the roots to fork. The soil needs to drain reasonably well whilst retaining moisture, which is why swedes do particularly well in the rich loams you find across much of Yorkshire and the Scottish Borders. If your soil is acidic (below pH 6.0), add garden lime to raise it, as this also helps prevent clubroot, a serious disease that affects all brassicas. Break down any large clods and remove stones, then rake the surface to create a fine tilth. The bed should be firm enough that it doesn’t sink dramatically when you walk on it, but not compacted.

Sowing Your Seeds

Timing is critical with swedes. I sow mine between late May and early June across most of the country, though you can push this to late April in milder southern counties. Too early and they’ll run to seed in hot weather, too late and they won’t develop properly before winter. Using a garden line, mark out drills about 1.5cm deep and 38cm apart. Sow seeds thinly along each row, aiming for roughly one seed every 5cm, though I usually sow a bit thicker as insurance against poor germination and pest damage. Cover the seeds lightly with soil and firm gently with the back of your rake. Water the drills thoroughly if the soil is dry. Germination typically takes 7 to 14 days depending on temperature and moisture levels. I always cover my newly sown rows with fleece or enviromesh immediately after sowing, as flea beetles will attack seedlings the moment they emerge, riddling the leaves with tiny holes that can kill young plants.

Thinning and Early Care

Once your seedlings have developed their first true leaves (not the initial seed leaves), it’s time for the first thinning. This is tedious work but absolutely necessary. Thin to about 10cm apart initially, then do a second thinning when plants are more established, leaving final spacing of 23 to 30cm between plants. Closer spacing produces smaller roots, which some people prefer, whilst wider spacing gives you proper giants. I thin in the evening and remove all the thinnings from the bed, as their scent can attract cabbage root fly. Keep the bed meticulously weeded during these early weeks, as swedes grow slowly at first and can’t compete with aggressive weeds. Water during dry spells, particularly on light soils, but don’t overdo it. Swedes are reasonably drought-tolerant once established, and too much water can lead to lush leaf growth at the expense of root development.

Ongoing Maintenance

Through summer, your main jobs are weeding, watering during extended dry periods, and watching for pests. The mesh or fleece can come off after about six weeks, though I often leave it on longer in areas with high pest pressure. Swedes don’t need feeding if you’ve prepared the soil properly, though a light application of a balanced organic fertiliser in midsummer won’t hurt if growth seems slow. As the roots begin to swell and push out of the ground, there’s no need to earth them up like you might with potatoes. The purple shoulders exposed to light are perfectly normal and actually sweeter than the buried portion. By late September, you should have decent-sized roots developing. Unlike many vegetables, swedes actually improve with a frost or two, which converts starches to sugars and enhances their flavour.

Harvesting and Storage

Swedes are ready to harvest from October onwards, typically 20 to 26 weeks after sowing. You can start lifting them when they reach about the size of a tennis ball, though most gardeners wait until they’re closer to a cricket ball or larger. I use a fork to loosen the soil around each root before pulling, as simply yanking them out can damage the crown. In milder parts of the country, particularly in the South West and coastal Wales, you can leave them in the ground all winter and harvest as needed. However, if you’re in an area prone to hard frosts or have heavy soil that becomes waterlogged, it’s better to lift them all by late November. Twist off the leaves, brush off excess soil (don’t wash them if you’re storing), and pack the roots in boxes of barely damp sand or sawdust in a cool, frost-free shed. Stored this way, they’ll keep until March easily.

Common Mistakes to Avoid

Sowing Too Early

The single biggest mistake I see people make is sowing swedes too early, often in April when they’re full of enthusiasm for the new growing season. Swedes are programmed to respond to day length, and early sowing combined with long summer days can trigger bolting (premature flowering). When a swede bolts, it puts all its energy into producing a flower stem rather than a useful root, and you end up with nothing edible. This is particularly problematic in southern England where spring warms up quickly. Wait until late May or early June, even if it feels late. Trust me, the plants will catch up, and you’ll get better roots that actually develop properly instead of woody, bitter failures.

Neglecting Pest Protection

Leaving young swede seedlings unprotected is asking for trouble. Flea beetles can devastate an entire crop within days, leaving the cotyledons and first true leaves so damaged that plants never recover. I learnt this the hard way during my first attempt at growing swedes, when I dismissed the tiny beetles as insignificant. By the time I realised the damage, it was too late to resow. Cabbage root fly is equally destructive but harder to spot, as it attacks below ground. The larvae tunnel into developing roots, making them inedible and prone to rot. Fine mesh or fleece barriers work brilliantly against both pests and are far more reliable than any organic spray. Yes, they’re a bit fiddly to install, but the protection is worth every minute of effort.

Overcrowding Plants

It’s tempting to skip thinning or to be too cautious with it, leaving plants closer together than recommended. Overcrowded swedes compete for nutrients, light, and water, resulting in small, malformed roots that never reach their potential. I’ve seen allotment plots where swedes were left at 10cm spacing all season, producing roots barely larger than radishes. Proper spacing might seem wasteful when you’re removing healthy seedlings, but each plant needs room to develop. The thinnings can go in the compost or, if you’re feeling adventurous, the young leaves can be cooked like spring greens. Be ruthless with your thinning, and you’ll be rewarded with proper, usable roots come autumn.

Growing in Acidic Soil

Swedes, like all brassicas, really struggle in acidic conditions and become highly susceptible to clubroot disease. If you’ve got naturally acidic soil, which is common in areas with high rainfall like parts of Wales, Scotland, and the Lake District, you need to address this before sowing. I test my soil every couple of years and add lime as needed, usually in autumn so it has time to work through the soil before spring. Clubroot is devastating and persists in soil for decades once established, causing roots to become distorted and swollen whilst plants remain stunted. There’s no cure, only prevention through maintaining the right pH and practising good crop rotation. If you know clubroot is present in your area, keeping pH above 7.0 significantly reduces infection rates.

Expert Tips

Choose the Right Variety

Not all swede varieties perform equally across different regions. I’ve had brilliant results with ‘Marian’, which is particularly reliable in northern areas and has good clubroot resistance. ‘Brora’ is another excellent choice, bred specifically for Scottish conditions but performing well anywhere in the country. For sweeter, more tender roots, try ‘Invitation’, though it’s slightly less hardy in severe winters. If you’re growing for storage, ‘Best of All’ lives up to its name with exceptional keeping qualities. Some gardeners prefer purple-topped varieties like ‘Ruby’, whilst others go for the traditional bronze-green types. Don’t be afraid to try different varieties and see what works best in your particular soil and climate.

Practice Strict Crop Rotation

Never grow swedes in the same spot year after year. As members of the brassica family, they’re susceptible to soil-borne diseases and pests that build up when you grow related crops (cabbage, kale, Brussels sprouts, turnips, radishes) in the same location. I follow a minimum four-year rotation, which means any given bed only grows brassicas once every four years. This dramatically reduces problems with clubroot, cabbage root fly, and nutrient depletion. Keep good records of what you plant where, as it’s surprisingly easy to forget your rotation plan from one year to the next. If you’re working with limited space, growing swedes in large containers with fresh compost each year can be an alternative, though you’ll need deep containers of at least 30cm.

Time Your Harvest for Peak Flavour

Whilst swedes can be harvested from early autumn onwards, the flavour really improves after they’ve experienced a few frosts. The cold triggers the conversion of starches to sugars, making the roots noticeably sweeter. I always wait until after the first proper frost before starting my main harvest, usually sometime in November. However, don’t leave them too long in heavy, wet soil, as they can become waterlogged and prone to rot. If you’re in an area with harsh winters, particularly in Scotland or upland areas, harvest everything before the ground freezes solid. In milder regions, you can adopt a middle approach: lift half the crop for storage and leave the rest in the ground with a thick mulch of straw for frost protection.

Water Consistently During Root Development

Whilst swedes tolerate dry conditions better than many vegetables, inconsistent watering during the crucial root development phase (typically August and September) can cause problems. Alternating between bone-dry and saturated soil often leads to splitting, where the outer layer of the root cracks as it expands too rapidly after rain following drought. I aim to keep the soil evenly moist during late summer, watering deeply once a week during dry spells rather than little and often. A mulch of compost or well-rotted grass clippings around plants helps retain moisture and suppress weeds. In very wet autumns, which we seem to get more frequently, there’s not much you can do except ensure your soil drains reasonably well and harvest before roots sit in waterlogged conditions for weeks.

Frequently Asked Questions

Can I grow swedes in containers?

Yes, you can grow swedes in containers, though they need deep pots of at least 30cm to accommodate the developing root. Choose a container with good drainage holes and fill it with a quality multipurpose compost mixed with some garden soil or loam-based compost for stability. You’ll need to water container-grown swedes more frequently than those in the ground, particularly during summer. Spacing can be slightly closer in containers, around 20cm between plants. The main advantage is that you can use fresh compost each year, completely avoiding soil-borne diseases like clubroot. However, yields are generally lower than in-ground growing, and containers dry out quickly during hot weather, which can affect root development.

What’s the difference between swedes and turnips?

Swedes and turnips are related but distinct vegetables with different growing requirements and characteristics. Swedes (Brassica napus) have yellow flesh, purple and cream skin, and a sweeter, denser texture. They take 20 to 26 weeks to mature and are sown in late spring for autumn and winter harvest. Turnips (Brassica rapa) typically have white flesh, can be all white or purple-topped, and have a sharper, more peppery flavour. They grow much faster, maturing in 6 to 10 weeks, and can be sown from spring through to late summer. In terms of hardiness, swedes are far superior for overwintering and improve with frost, whilst turnips are better as a quick-growing catch crop. Nutritionally, swedes contain more vitamins and have a lower water content, making them better for storage.

How do I prevent my swedes from going woody?

Woody swedes are usually the result of stress during growth or leaving them in the ground too long past maturity. The most common causes are irregular watering, poor soil fertility, or harvesting too late in spring when they’ve been in the ground since autumn. To prevent woodiness, ensure your soil is well-prepared with plenty of organic matter before sowing, and maintain consistent moisture levels during the growing season. Harvest swedes at the right stage, when they’re between cricket ball and small melon size, rather than leaving them to grow enormous. If you’re storing them in the ground over winter, aim to harvest by late February or early March at the latest before they put energy into producing spring growth. Choosing naturally tender varieties also helps.

Why are my swede leaves full of holes?

Small holes in swede leaves are almost certainly caused by flea beetles, tiny jumping insects that are particularly active in warm, dry weather. They’re most damaging to young seedlings, where severe attacks can kill plants or stunt them permanently. Larger, irregular holes might indicate caterpillars from cabbage white butterflies or moths. The best prevention for flea beetles is covering rows with fleece or fine mesh immediately after sowing and keeping it in place for at least six weeks. Keeping soil moist and encouraging rapid early growth helps seedlings outgrow the vulnerable stage faster. For caterpillars, check plants regularly and remove any you find by hand. Whilst the holes look alarming, plants usually recover once they’re larger, and moderate leaf damage doesn’t affect root development significantly.

Is it too late to sow swedes in July?

July is generally too late for sowing swedes in most of the country, as they won’t have sufficient time to develop proper roots before winter slows growth dramatically. Swedes need 20 to 26 weeks from sowing to harvest, so a July sowing would be looking at maturity in December or January, when growth has essentially stopped. You might get away with early July sowings in mild southern counties or coastal areas with extended growing seasons, but the roots will likely be smaller than from May or June sowings. In northern regions, Scotland, or upland areas, anything after mid-June is pushing it. If you’ve missed the swede window, consider sowing turnips instead, which mature much faster and can be sown successfully into August for autumn harvest.

Can swedes recover from frost damage?

Mature swedes are extremely frost-hardy and actually benefit from light to moderate frosts, which improve their flavour. The roots can withstand temperatures down to minus 10°C when they’re in the ground, particularly if you mound soil or mulch over the crowns. However, once lifted and stored, they’re vulnerable to freezing, which turns them to mush. Young seedlings are more susceptible to frost damage, and a hard early frost in May can set them back significantly or kill them. If the growing tips (the central leaves) are damaged by frost but the outer leaves remain healthy, plants usually recover and continue growing, though this delays maturity. If you’re in a frost-prone area and sowing early, keep fleece handy to protect seedlings if unexpected late frosts are forecast. Once plants are established and roots are developing, you can stop worrying about frost.

Wrapping Up

Growing swedes successfully comes down to getting the basics right: proper timing, well-prepared soil, adequate spacing, and protection from pests during the vulnerable early stages. They’re not difficult vegetables, but they do require patience and a willingness to wait the full growing season for results. I’ve found them to be remarkably forgiving once established, tolerating our changeable weather better than many more popular crops. The satisfaction of pulling a perfect swede from the ground on a cold November day, knowing it’ll store for months and provide nutritious meals through winter, makes the effort worthwhile. Start with good soil preparation, sow at the right time, protect those seedlings, and you’ll be rewarded with a crop that punches well above its weight in terms of reliability and storage potential. Give them a try this growing season, and you might just find yourself wondering why you didn’t start growing them sooner.

Author: Megan Walker

Megan focuses on seasonal food, kitchen garden growing, and how households can reconnect with where their food comes from. Her writing blends practical growing advice with ideas for cooking and eating in season. With a passion for fresh ingredients and sustainable living, Megan’s articles help readers make the most of local produce while supporting British farms.