At a glance
Ease of culture: Moderate
Where: All zones (except tropical Brussels sprouts)
Best climate: Cool season
When: Autumn, winter, spring
Spacing: Broccoli and cauliflower 40cm, Brussels sprouts 50-90cm
Harvest: 12-16 weeks
• These are cool- to mild-season crops that can handle quite cold conditions
• All are frost hardy. Brussels sprouts are particularly hardy and will tolerate quite severe frost. This is said to improve the quality of sprouts.
• Broccoli is the most warm-hardy and the best of this group for planting in tropical and subtropical climates.
• Cauliflower and Brussels sprouts will grow in southern subtropical regions, but must be planted in early autumn to benefit from a long cool season
• Find a spot in full sun with at least 6 hours direct sunlight per day
• These plants are easily damaged, so choose a spot with protection from strong wind
• Brassicas demand a rich, well-drained soil.
• Dig in plenty of compost and well-rotted manure before planting and incorporate it to a spade’s depth.
• These are heavy feeders so incorporate some fertilisers too – a good handful of blood and bone, and a tight fistful of sulphate of potash per square metre.
• Brassica like a slightly acidic to neutral soil. If your soil is acidic, add some lime at the rate of one handful per square metre.
• Water it in well and let it settle for a week or so before planting
• Seeds can be sown directly in the soil, but for the most reliable results, sow seeds in small pots first and plant out later.
• The best temperature for seed germination is 10-25°C
• The sewing time varies greatly depending on which brassica you are growing and where you live. Refer to the sowing guide below
• Plant out seedlings when well established – about 4-6 weeks after sewing
• These plants topple over easily in strong wind. Plant seedlings a little deeper to cover the lowest leaves. This will help to stabilise the plants.
• Space broccoli and cauliflower seedlings 40cm apart in rows 60cm apart, and Brussels sprouts 50-90cm apart in rows 90cm apart.