Broccoli Sprouting Calabrese

Climate and Season

Broccoli prefers cool to mild temperatures, making it ideal for growing in most parts of Australia during autumn, winter, and early spring. 

 Frost Tolerance:

• Broccoli can tolerate light frost, which can even improve its flavour. 

 Heat Sensitivity:

• High temperatures can cause bolting (premature flowering), so avoid planting in summer in hot regions. 

Soil Preparation

Broccoli requires well-draining, fertile soil with a slightly acidic to neutral pH. 

 Soil pH:

• 6.0–7.0. 

 Soil Type:

• Loamy soil rich in organic matter. 

 Preparation: 

• Dig the soil to a depth of 30 cm. 
• Incorporate well-rotted compost or aged manure to improve fertility and drainage. 
• Add a balanced organic fertilizer (e.g., blood and bone or chicken manure pellets) before planting. 

Seed Starting

In trays:

• Start seeds indoors 4–6 weeks before the last expected frost date. 
• Sow seeds 3 mm deep in seed trays or pots. 
• Transplant seedlings when they are 10–15 cm tall and have 4–6 true leaves. 

 Direct Sowing: 

• Sow seeds directly into the garden bed, spacing them 30 cm apart. 

Depth:

• Plant seedlings at the same depth as they were in their pots. 

Watering

Broccoli requires consistent moisture to grow well. 

Watering Frequency:

• Water deeply 2–3 times per week, depending on rainfall and soil type. 

 Avoid Overwatering:

• Ensure the soil is moist but not waterlogged, as this can lead to root rot. 

 Mulching:

• Apply a layer of organic mulch to retain soil moisture and regulate temperature. 

Fertilising

At Planting:

• Broccoli is a heavy feeder, so it is important that the soil is enriched with compost, manures or balanced fertiliser before planting
• Benefits from fortnightly applications of liquid seaweed and fish solutions.

Pest and Disease Management

Broccoli is susceptible to several pests and diseases. 

Common Pests: 

• Cabbage white butterfly caterpillars: Use row covers or spray with *Bacillus thuringiensis* (Bt). You will find it under the brand name Dipel at most garden centres.
• Aphids: Spray with soapy water or introduce beneficial insects like ladybugs. 
• Snails and slugs: Use beer traps or organic pellets. 

Common Diseases: 

• Clubroot: Ensure proper soil drainage and rotate crops. 
• Downy mildew: Avoid overhead watering and ensure good air circulation. 
• Black rot: Remove infected plants and practice crop rotation. 

Harvesting

Timing:

• Harvest broccoli when the central head is firm, tight, and dark green, typically 10–16 weeks after planting. 

Method:

• Cut the main head at an angle with a sharp knife, leaving 10–15 cm of stem. 
• Side Shoots: After harvesting the main head, smaller side shoots will develop and can be harvested for several weeks. 

Companion Planting

Good Companions

Herbs:

• Dill, rosemary, sage, and mint repel pests like cabbage moths and aphids. 

Alliums:

• Garlic, onions, and leeks deter aphids and other pests. 

Leafy Greens:

• Lettuce and spinach provide ground cover, reducing weeds and retaining soil moisture. 

Root Vegetables:

• Beetroot and celery grow well alongside broccoli without competing for nutrients. 

Flowers:

• Marigolds and nasturtiums repel pests and attract beneficial insects. 

Plants to Avoid

Other Brassicas:

• Avoid planting broccoli near cabbage, cauliflower, or kale, as they attract the same pests and compete for nutrients. 

Strawberries:

• They can inhibit broccoli growth. 

Tomatoes:

• They may compete for nutrients and space. 

Crop Rotation

• To prevent soilborne diseases and nutrient depletion, practice crop rotation. 
• Avoid planting broccoli or other brassicas in the same spot more than once every 3–4 years. 
• Follow broccoli with legumes (e.g., beans or peas) to replenish soil nitrogen. 

Tips for Success

Succession Planting:

• Sow seeds every 2–3 weeks for a continuous harvest. 

Shade Cloth:

• Use shade cloth in warmer regions to protect plants from excessive heat. 

Regular Monitoring:

• Check plants weekly for pests and diseases.