How to grow collard greens
Overview
Collard greens are a non-heading brassica grown for their large, nutritious leaves. They thrive in cool weather but tolerate more heat than many cabbage relatives, making them a versatile cool-season crop. Regular harvesting from the outside encourages continuous leaf production.
Varieties
- Georgia — A classic heirloom with large, dark green leaves; very cold-hardy and reliable in Australian cool seasons.
- Champion — Compact, vigorous variety with tender leaves; good for smaller gardens and pots.
- Vates — Slow to bolt, with smooth, blue-green leaves; ideal for extended harvests in temperate and subtropical zones.
- Blue Max — Hybrid with excellent heat tolerance and upright growth; performs well in warmer areas like subtropical gardens.
Soil Preparation
Collard greens prefer fertile, well-drained soil with pH 6.0–7.5. Enrich the bed with compost or well-rotted manure before planting. Ensure good drainage to prevent root rot; raised beds are beneficial in heavy clay soils.
Growing Guide
Sow seeds 1–2 cm deep in well-drained, fertile soil in full sun. Space plants 45–60 cm apart, with rows 60 cm apart. Keep soil evenly moist, especially during dry spells, and mulch around plants to retain moisture and suppress weeds. For best quality, grow through autumn and winter; in cooler zones, a spring planting also works.
Sowing
Sow seeds 1 cm deep directly in the garden or in seed trays. Thin seedlings to 45 cm apart for full-sized plants. Germination takes 5–10 days at 10–30°C. Transplant seedlings when they have 4–6 true leaves.
Care
Feed with a balanced nitrogen-rich fertiliser (e.g., blood and bone) every 4–6 weeks during active growth. Remove yellowing lower leaves to improve air circulation and redirect energy to new growth. Apply organic mulch (straw, sugarcane) to retain moisture and keep roots cool.
Companion Planting
Good companions include beetroot, carrots, celery, onions, peas, and potatoes. Avoid planting near other brassicas (broccoli, cabbage, kale, cauliflower) to reduce share of pests and disease. Dill and chamomile nearby can help repel cabbage white butterfly.
Common Pests & Risks
Cabbage white butterfly caterpillars, aphids, and flea beetles are common. Use fine netting or row covers to exclude butterflies, apply insecticidal soap for aphids, and control flea beetles with diatomaceous earth or neem oil. Healthy, well-watered plants are less susceptible.
Harvesting
Pick outer leaves when they reach 20–30 cm long, leaving the inner rosette to keep producing. Harvest begins 60–80 days from sowing; regular picking encourages tender new growth.
In the Kitchen
Leaves can be eaten raw in salads or cooked (braised, steamed, stir-fried). They have a mild, slightly cabbagy flavour that improves after frost. Store fresh leaves in a plastic bag in the fridge for up to a week; blanch and freeze for longer storage.
Troubleshooting
Yellowing lower leaves: nitrogen deficiency – apply a balanced fertiliser. Holes in leaves: cabbage caterpillar – hand pick or use BT (Bacillus thuringiensis). Slow growth: cold soil or insufficient water – ensure consistent moisture and wait for warmer weather. Bolting: heat stress – harvest promptly and provide partial shade in hot spells. Sticky residue: aphid infestation – spray with soapy water or neem oil.