VegetablerootStraightforward

Swede

Brassica napus

A long-season winter root sown in early summer and lifted from autumn onwards, sweeter after frost and content to stay in the ground until needed. It occupies its space for five months, which is the main argument against it on a small plot and the main argument for it on a large one.

Position: Full sun
Water: moderate demand
Drainage: Moisture-retentive
Grows to: 40–50 cm × 30 cm
Hardiness: H5
Harvest: October to February
Difficulty: Straightforward

August

Nothing to do

No sowing, planting, harvesting or pruning window falls in August.

Swede’s year

Resolved for United Kingdom (general). Every window is stored against a climate event rather than a date, so a late frost pocket runs later than the band shows. What else August calls for.

Activity	J	F	M	A	M	J	J	A	S	O	N	D
Sow outdoors					May.	June.
Harvest	January.	February.								October.	November.	December.

Timing that travels

The band above resolves this plant's windows into months for one region. These are the windows themselves, stored against a climate event rather than a date — which is the form that survives being carried to a colder garden, a frost pocket, or next year.

Conditions it needs

Light: Full sun
Frost: Very hardy
Hardiness rating: H5 (RHS)
Grows best at: 10–18 °C
Germinates at: 5–25 °C
Soil: Loam, Clay
Soil pH: 6–7.5
Drainage: Moisture-retentive
Water needs: moderate
Drought: poor tolerance
Waterlogging: moderate tolerance
Heat: poor tolerance
Wind and exposure: good tolerance

Where these figures come from

LightSourced guidancemoderate confidence: Royal Horticultural Society: Swede — position
Checked 2026-08-13
FrostSourced guidancehigh confidence: Royal Horticultural Society: Swede — hardiness
Checked 2026-08-13
Hardiness ratingSourced guidancemoderate confidence: Royal Horticultural Society: RHS hardiness ratings
Checked 2026-08-13
Grows best atSourced guidancemoderate confidence: Royal Horticultural Society: Swede — temperature
Checked 2026-08-13
Germinates atSourced guidancemoderate confidence: Royal Horticultural Society: Seed germination temperatures
Checked 2026-08-13
SoilSourced guidancemoderate confidence: Royal Horticultural Society: Swede — soil
Checked 2026-08-13
Soil pHSourced guidancemoderate confidence: Plant Finder — Missouri Botanical Garden: Brassica napus — culture
Checked 2026-08-13
DrainageSourced guidancemoderate confidence: Royal Horticultural Society: Swede — soil
Checked 2026-08-13
Water needsHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
DroughtHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
WaterloggingHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
HeatHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Wind and exposureHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

On your soil

Computed by comparing this plant's recorded requirements against each soil's recorded characteristics. A recorded horticultural fact overrides the comparison where GrowingHQ holds one.

Soil	Verdict	Why
Heavy clay	Prefers this soil	Heavy clay suits Swede as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. Clay is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Sandy	Works, with one condition	Swede will crop on sandy, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Chalky and alkaline	Works, with one condition	Swede will crop on chalky and alkaline, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Loam	Prefers this soil	Loam suits Swede as it stands: The pH suits it: it wants 6 to 7.5, and this soil is in that range. Loam is among the soils it is recorded as suiting. The soil holds moisture, which saves a great deal of watering.
Silty	Grows well here	Swede grows perfectly well on silty without special measures, though it is not the soil it would choose.
Peaty and acid	Grows well here	Swede grows perfectly well on peaty and acid without special measures, though it is not the soil it would choose.
Shallow over rock	Works, with one condition	Swede will crop on shallow over rock, but one thing has to be dealt with first. It has little drought tolerance and this soil dries out fast — it will check and bolt in the first dry spell without watering.Water and mulch will carry it through. On this soil the watering is not optional in a dry spell, which is the difference between a crop and a failure.
Made ground and urban soil	Grows well here	Swede grows perfectly well on made ground and urban soil without special measures, though it is not the soil it would choose.

Not sure which you have? Four hand tests will settle it.

Space and spacing

Mature height: 40–50 cm
Mature spread: 30 cm
Rooting depth: 40 cm
Spacing: 23–30 cm apart

Where these figures come from

Mature heightHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Mature spreadHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
Rooting depthHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13
SpacingSourced guidancemoderate confidence: Royal Horticultural Society: Swede — spacing
Checked 2026-08-13

Measured centre to centre. Plants set closer than this compete for light and water long before they look crowded, and the crowding cannot be undone once they are in.

Where and how you can grow it

Each way of growing is assessed separately, and “not assessed” is a real answer rather than a gap we have filled in with a guess.

Method	Suitability	What it needs
Open ground	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Traditional dug bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Raised bed	Well suited source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13
Container	Marginal source Sourced guidancemoderate confidence Royal Horticultural Society: Growing method suitability Checked 2026-08-13	Large and long-season — a poor use of container space
Hydroponics	Marginal source GrowingHQ editorial positionmoderate confidence A large root taking most of a season, which is the carrot's disqualification with a longer timescale attached. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13
Greenhouse	Marginal source Sourced guidancemoderate confidence Agriculture and Horticulture Development Board — AHDB: Root crops under protection Checked 2026-08-13
Polytunnel	Marginal source Sourced guidancemoderate confidence Agriculture and Horticulture Development Board — AHDB: Root crops under protection Checked 2026-08-13

Growing it

ThinningThin to 23 cm as soon as the seedlings can be handled. Swede needs the whole season to bulk up and cannot make up for a crowded start.
WateringWater through dry spells in July and August. A midsummer check is what produces small woody roots, and it is the only common failure with this crop.
FeedingGrow on ground manured for a previous crop rather than freshly manured ground, which produces forked and fanged roots. Swedes need little else; excess nitrogen gives leaf at the expense of the root.
SowingSow direct into firm, settled ground from late spring, thinly, and thin the seedlings early to their final spacing. Swedes sown too early bolt, and swedes left crowded make small woody roots — the thinning matters more than anything else done to the crop.

Where this guidance comes from

ThinningSourced guidancehigh confidence: Royal Horticultural Society: Swede — care
Checked 2026-08-13
WateringSourced guidancehigh confidence: Royal Horticultural Society: Swede — care
Checked 2026-08-13
FeedingSourced guidancemoderate confidence: Royal Horticultural Society: Swede — cultivation
Checked 2026-08-13
SowingSourced guidancemoderate confidence: Royal Horticultural Society: Swede — sowing
Checked 2026-08-13

Is it worth putting under cover?

Whether it will grow there is on the methods table above. This is whether the space is well spent, which is a different question and usually the one being asked.

Structure	What protection is worth	What decides it
Greenhouse	No real benefit source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Occupies protected ground for months to produce something that grows perfectly well outdoors. The cost is not the crop, it is everything that could have been there instead. A swede takes most of a season and is hardy enough to be lifted from frozen ground.
Polytunnel	No real benefit source GrowingHQ editorial positionmoderate confidence What protection is worth for this crop, judged against the same standard as every other record in this file. GrowingHQ editorial synthesis — GrowingHQ Checked 2026-08-13	Occupies protected ground for months to produce something that grows perfectly well outdoors. The cost is not the crop, it is everything that could have been there instead.

Growing it without soil

Nearly anything can be grown in a soilless system by somebody with enough equipment. The useful question is whether it is worth it, in which technique, and what goes wrong.

Not worth it

It can be made to grow, but a soilless system is the wrong tool — usually because of rooting volume, running cost, or a result no better than a pot of compost.

source

GrowingHQ editorial positionmoderate confidence

A large root taking most of a season, which is the carrot's disqualification with a longer timescale attached.

GrowingHQ editorial synthesis — GrowingHQ

Checked 2026-08-13

Also improved by frost, like the parsnip, so a warm system costs flavour as well as space.

Techniques that suit it

Drip-fed mediumSolution is dripped into an inert medium around each plant. The most forgiving technique and the one that suits large, long-season, heavy crops.

Horticultural consensusDepends on conditionsmoderate confidence

Applies when: Deep medium only, and no better than a deep pot.

No external citation — see the evidence type above.

Checked 2026-08-13

Root space: Deep and uniform, which is exactly what equipment makes expensive.
pH band: 5.5–6.5

Where these figures come from

Root spaceHorticultural consensusmoderate confidence

No external citation — see the evidence type above.

Checked 2026-08-13

pH bandSourced guidancehigh confidence

Outside roughly this band, individual nutrients become unavailable even when they are present in the solution — which is why a crop can starve in a full reservoir.

Purdue Extension — Purdue University: Hydroponic solution management — pH

Checked 2026-08-13

No nutrient recipes here

GrowingHQ records pH bands, which are measurable properties of nutrient availability, and deliberately records no EC or PPM targets and no mixing instructions. Published targets vary by cultivar, growth stage, water source and technique, and the figures that apply to your system are on the product you bought.

Harvesting

When it is readyReady once the root is about the size of a grapefruit and the shoulders stand proud of the soil — usually from October, and the flavour is distinctly better after the first frosts have been on them. Lift them small rather than letting them get very large, which makes them woody and prone to splitting.
How to pick itEase up with a fork and pull by the leaf bases. Swedes stand in the ground through the winter in all but the hardest weather and keep better there than in a shed, so lift as needed and leave the rest; a covering of straw makes them liftable in frozen ground.
Keeping itBest left in the ground and lifted as wanted. Lifted roots keep for a few months in a cool shed with the tops twisted off.

Where the harvest guidance comes from

When it is readySourced guidancehigh confidence: Royal Horticultural Society: Swede — harvesting
Checked 2026-08-13
How to pick itSourced guidancehigh confidence: Royal Horticultural Society: Swede — harvesting
Checked 2026-08-13
Keeping itHorticultural consensusmoderate confidence: No external citation — see the evidence type above.
Checked 2026-08-13

What goes wrong

Problem	How often	Notes
Cabbage root fly	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	The maggots tunnel the root itself, so the damage is found when the crop is lifted.
Boron deficiency	occasional source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Brown heart is the classic swede disorder on light or over-limed ground.
Flea beetle	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Pits the seedling leaves in a dry spring; a crop past four true leaves outgrows it.
Clubroot	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13
Powdery mildew	common source Horticultural consensusmoderate confidence No external citation — see the evidence type above. Checked 2026-08-13	Late-summer mildew is normal on swede and rarely costs the crop.

Sources for this page

Agriculture and Horticulture Development Board · GrowingHQ editorial synthesis · Plant Finder · Royal Horticultural Society

Each figure on this page carries its own citation, under the “where these figures come from” note in its section. Record last reviewed 2026-08-14.