How to grow turnip
Overview
Turnip (Brassica rapa subsp. rapa) is a fast-growing cool-season root vegetable grown for its crisp, mildly spicy roots and nutritious leaves. It requires consistent moisture and mild temperatures (10–20°C) to develop tender, non-woody roots.
Varieties
- Purple Top White Globe — Classic heirloom with purple shoulders and white base; reliable in Australian cool seasons.
- Milan Purple Top — Early maturing flat turnip with purple-red top; good for quick crops.
- Snowball — All-white round turnip with mild flavour; popular for baby roots and salads.
Soil Preparation
Turnip prefers well-drained, loamy soil with pH 6.0–7.0. Incorporate well-rotted compost or aged manure before planting to boost organic matter and drainage. Avoid heavy clay or compacted soil which can cause misshapen or forked roots.
Growing Guide
Direct sow turnip seeds 1 cm deep and 2.5 cm apart in rows 30 cm apart, in full sun and well-drained soil rich in organic matter. Thin seedlings to 10 cm apart once they reach 5 cm tall to allow roots to develop properly. Keep soil evenly moist throughout growth; check water deeply during dry spells. Sow in succession every 3–4 weeks for a continuous harvest. Avoid transplanting as root disturbance can cause forking.
Sowing
Sow seeds directly into the garden bed 1 cm deep, 2.5 cm apart in rows 30 cm apart. Germination takes 5–10 days at soil temperatures of 10–25°C. Thin seedlings gradually to 10 cm apart for best root development. Succession sow every 3 weeks for a longer harvest.
Care
Apply a balanced nitrogen-rich fertiliser (e.g., blood and bone or liquid seaweed) every 3–4 weeks during active growth. Remove yellowing or crowded leaves to improve airflow and reduce disease risk. Mulch around plants to conserve moisture and keep soil cool.
Companion Planting
Turnip grows well with peas, beans, lettuce, and spinach. Avoid planting near other brassicas such as cabbage, broccoli, and kale to reduce pest and disease pressure. Mint and dill may also benefit by repelling pests.
Common Pests & Risks
Cabbage white caterpillars are a common pest; control with floating row covers or Bacillus thuringiensis. Aphids and flea beetles may also attack; use insecticidal soap for aphids and diatomaceous earth or sticky traps for flea beetles. Clubroot can occur in acidic soil; maintain pH ≥ 6.0 and rotate crops.
Harvesting
Harvest turnip roots when they reach 5–8 cm in diameter for the best flavour and tenderness, typically 6–10 weeks from sowing. Leaves can be harvested earlier as greens, taking outer leaves and leaving the centre to grow.
In the Kitchen
Turnip roots are delicious raw in salads, roasted, mashed, or pickled. The greens are highly nutritious and can be sautéed, steamed, or added to soups. Store roots in a cool, dark place (fridge or cellar) with tops removed to keep for several weeks.
Troubleshooting
Roots are woody and tough: caused by slow growth from heat or drought; water consistently and harvest promptly within 10 weeks. Poor root formation: cause is overcrowding or insufficient thinning; thin to 10 cm apart and ensure loose soil. Holes in leaves: flea beetles or cabbage caterpillars; use row covers or organic sprays. Bolting (flowering): due to sudden heat or stress; choose bolt-resistant varieties and time planting for cooler months. Yellow leaves: nitrogen deficiency or water stress; feed with balanced fertiliser and check moisture.