Plant Library swede
Vegetable · Full Sun

How to grow swede

Brassica napus var. napobrassica
swede
Photo: Kamil Czaiński / Wikimedia Commons (CC BY-SA 4.0)
☀️
Full Sun
Sun
💧
Medium
Water
📐
20–30 cm
Spacing
🌾
90–120 days
Days to harvest

Overview

Swede (Brassica napus var. napobrassica) is a cool-season root vegetable grown for its large, sweet-flavoured bulbs. It requires consistent moisture and cool temperatures to develop tender roots without becoming woody.

Varieties

  • Champion — A popular purple-top swede with smooth skin and sweet, creamy flesh, reliable in cool climates.
  • Marian — A high-yielding variety with good resistance to clubroot, suitable for temperate and cool zones.
  • Helenor — A late-maturing swede with excellent storage qualities and mild flavour.

Soil Preparation

Swede prefers deep, well-drained soil with a pH of 6.0–7.0. Enrich with well-rotted compost or aged manure before planting. Avoid freshly manured soil to prevent root forking.

Growing Guide

Sow swede seeds directly into well-drained, fertile soil in full sun. Plant seeds 1 cm deep, 15 cm apart in rows 30 cm apart. Thin seedlings to 20–25 cm apart once they reach 10 cm tall. Keep soil consistently moist, especially during root swelling. Avoid transplanting to prevent root disturbance.

Sowing

Sow seeds directly into the garden bed at 1 cm depth, spacing seeds 15 cm apart in rows 30 cm apart. Germination takes 5–10 days. Thin to 20–25 cm apart once seedlings are established. Direct sowing is preferred over transplanting.

Care

Apply a potassium-rich fertiliser (e.g., sulphate of potash) when roots begin to swell. Avoid high-nitrogen feeds after root formation to prevent forking. Remove yellowing lower leaves to improve air circulation and reduce disease.

Companion Planting

Good companions include peas, beans, onions, and potatoes. Avoid planting near other brassicas like cabbage, broccoli, and kale to reduce pest and disease pressure.

Common Pests & Risks

Cabbage white caterpillars can be controlled with netting or Bacillus thuringiensis. Aphids and flea beetles may be managed with insecticidal soap or diatomaceous earth. Rotate crops to reduce soil-borne diseases like clubroot.

Harvesting

Harvest swede roots when they reach 8–12 cm in diameter, typically 12–16 weeks after sowing. Lift roots gently with a fork, trim tops, and store in a cool, dark place. Smaller roots are sweeter and more tender.

In the Kitchen

Swede can be roasted, mashed, or added to soups and stews. Peel before cooking as the skin is tough. Store in a cool, dark place for up to several months.

Troubleshooting

Root forking: caused by high nitrogen or stony soil; avoid fresh manure and remove stones. Woody roots: due to hot weather or delayed harvest; plant early and harvest promptly. Yellow leaves: nitrogen deficiency or overwatering; feed with balanced fertiliser and improve drainage. Small roots: overcrowding or poor soil; thin seedlings and enrich soil. Pests: cabbage white caterpillars and aphids; use netting or insecticidal soap.

Planting Calendar

Climate zone
Sow
Transplant
Harvest
Cool Hobart · Canberra · highlands
Sep–Jan
Mar–Jul
Temperate Melbourne · Adelaide · coastal NSW · most of NZ
Aug–Feb
Feb–Aug
Mediterranean Perth · Eyre Peninsula
Mar–Jun
Jul–Oct

Common Questions

How long does swede take to grow?
Swede typically takes 12–16 weeks from sowing to harvest, depending on the variety and growing conditions.
Can swede grow in a pot?
Yes, swede can be grown in a deep pot (at least 30 cm deep) with good drainage, but yields may be smaller.
When should I plant swede in Australia?
In cool and temperate zones, sow from spring to early summer. In Mediterranean zones, sow in autumn for winter harvest.
How much water does swede need?
Swede needs consistent moisture, about 2–3 cm of water per week. Keep soil evenly moist, especially during root swelling.
What are good companion plants for swede?
Peas, beans, onions, and potatoes are good companions. Avoid planting near other brassicas.
Why are my swede roots forked?
Forking is usually caused by high nitrogen levels or stony soil. Avoid fresh manure and remove stones before planting.
Can swede tolerate frost?
Yes, swede is very frost-tolerant and can be left in the ground over winter in cool climates, improving sweetness.
How do I store swede after harvest?
Store swede in a cool, dark, humid place like a root cellar or refrigerator. It can keep for several months.

Quick Facts

Sun Full Sun
Water Medium
Spacing 20–30 cm
Days to harvest 90–120
Frost tolerance High

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