How to grow broccoli raab
Overview
Broccoli raab (Brassica rapa var. ruvo) is a fast-growing cool-season brassica grown for its tender shoots, leaves, and stems, not a true head. It matures in 40–60 days with a mildly bitter flavour prized in Italian cuisine. Success hinges on cool weather and steady moisture to prevent premature bolting.
Varieties
- Quarantina — Early-maturing variety with tender, sweet shoots ideal for cool Australian and New Zealand gardens.
- Sessantina — Slightly later than Quarantina, with excellent flavour and good regrowth potential for multiple harvests.
Soil Preparation
Enrich soil with well-rotted compost or aged manure before planting for a steady supply of nutrients. Aim for a pH of 6.0–7.0 and ensure excellent drainage. Add a balanced slow-release fertiliser at sowing time.
Growing Guide
Sow seeds directly 0.5–1 cm deep in rich, well-drained soil in full sun. Thin seedlings to 10–15 cm apart with rows 30 cm apart. Keep soil consistently moist and apply a thin mulch to retain cool root temperatures. In hot weather, use shade cloth or time plantings to avoid summer heat. For a continuous harvest, sow successional crops every 2–3 weeks during the growing season.
Sowing
Direct sow in rows or beds 0.5–1 cm deep; germination takes 4–8 days in cool soil. Thin to 10–15 cm spacing after seedlings emerge. Transplant is possible but not necessary as they grow quickly.
Care
Feed every 2–3 weeks with a balanced liquid fertiliser during active growth to support leafy shoot production. Remove any yellowing lower leaves to improve airflow. No pruning is needed; just regular harvesting encourages new shoots.
Companion Planting
Pair broccoli raab with onions, garlic, beetroot, lettuce, peas, and dill to deter pests and improve space use. Avoid planting near other brassicas (cabbage, kale, cauliflower, broccoli) to reduce pest and disease carryover.
Common Pests & Risks
Watch for flea beetles (small holes on leaves), aphids (stunted growth, sticky residue), and caterpillars (chewed leaves). Control with diatomaceous earth or floating row covers for flea beetles; spray aphids with a soap solution or neem oil; hand-pick caterpillars or use Bacillus thuringiensis (Bt).
Harvesting
Harvest main shoots when they reach 15–20 cm tall and buds have formed but not yet opened—typically 40–60 days after sowing. Use a sharp knife or scissors to cut 5–10 cm above the base, leaving lower leaves to encourage side shoots for repeat picking.
In the Kitchen
Use shoots and tender leaves sautéed with garlic and chilli for a classic Italian side, or blanch briefly then add to pasta and risotto. Store in a plastic bag in the fridge for up to 4 days; blanch and freeze for longer storage.
Troubleshooting
Leaves with small round holes: flea beetles - use diatomaceous earth or row covers. Yellow leaves: nitrogen deficiency or overwatering - feed with liquid fertiliser and improve drainage. Plants bolting early: heat stress or water fluctuation - provide shade and steady moisture. Stunted growth: compacted soil or poor nutrition - loosen soil and add compost. Bitter taste: plant too mature or water-stressed - harvest earlier and keep soil moist.