Calabrese Broccoli

01 About

Calabrese is the green-headed broccoli sold in supermarkets — fast-growing, rewarding, and ready in 10–12 weeks from sowing. Cut the large central head first while still tight and dark green, then harvest the flush of side shoots that follow for several more weeks. Sow direct into its final position — calabrese dislikes root disturbance and transplants poorly.

02 What to Grow

Calabrese is one of the most satisfying crops to grow — it goes from seed to harvest in 10–12 weeks and produces first a large domed central head, then weeks of tender side shoots that many gardeners consider more flavourful than the head itself. Choose F1 varieties for uniformity and reliability; heritage open-pollinated types like Di Cicco and Waltham 29 produce smaller heads but extraordinary side shoot crops over a long season.

03 Varieties

The number of varieties shown for each crop is based on UK consumption data (2025/26) — the more popular the crop, the more variety choices we include.

🥦 Classic F1 Calabrese

Fast-maturing F1 varieties producing large central heads followed by generous side shoots. The reliable core of calabrese growing.

Marathon F1

Classic

The benchmark UK calabrese. Large, tight central head with excellent side shoot production. Good clubroot tolerance. Very consistent across different soil types and weather conditions.

• AGM
• Reliable
• High Yield
• Beginners

Ironman F1

Classic

Outstanding heat and drought tolerance. Very uniform, dense heads. Performs well in variable UK summers when other varieties struggle. Good resistance to downy mildew.

• AGM
• Heat Tolerant
• Reliable
• Disease Resistant

Fiesta F1

Classic

A variety with excellent disease resistance and a large domed head. Generous side shoot production over a long season. Tolerates variable weather better than most calabrese varieties.

• Disease Resistant
• High Yield

Belstar F1

Classic

Fine-beaded, beautifully domed heads with outstanding flavour. AGM variety. Medium plant size suitable for successional cropping. One of the best-tasting calabrese varieties for UK gardeners.

• AGM
• ⭐ Flavour
• Successional

Chevalier F1

Classic

Very high-yielding variety with large, tight heads and exceptional side shoot production after cutting. Popular with allotment growers for its consistency across a wide range of soil types.

• High Yield
• Reliable
• Allotment

Monflor F1

Classic

Compact habit ideal for raised beds and smaller plots. Uniform dome-shaped heads with fine florets. Side shoot production continues for weeks after the central head is cut.

• Compact
• Raised Bed

🌿 Heritage & Unusual

Open-pollinated heritage varieties and distinctive types for gardeners who want something beyond supermarket standard.

Waltham 29

Heritage

Classic heritage open-pollinated variety. Heavy side shoot production — the shoots are often more prolific and flavoursome than the central head. Excellent for late-season cropping into October. Seed-saveable.

• Heritage
• ⭐ Flavour
• Seed Saving

Di Cicco

Heritage

Traditional Italian heritage variety producing multiple small heads rather than one large central one. Extremely productive over a very long season. Open-pollinated — seed can be saved year to year.

• Heritage
• High Yield
• Seed Saving

Romanesco

Unusual

Spectacular lime-green fractal heads with a precise spiral pattern unlike any other brassica. Milder, nuttier flavour than standard calabrese. Takes longer to mature but is one of the most striking crops in the autumn garden.

• Heritage
• ⭐ Flavour
• Unusual

04 Where to Source

Calabrese seed is available from all main UK seed companies and garden centres. F1 varieties (Marathon, Ironman, Belstar) are widely available. Heritage types are best ordered from specialist online suppliers. Plug plants appear in garden centres from April and are a reliable option if the early sowing window has passed.

05 Planting Options

🌱 Direct Sowing (Standard)

Always sow direct into the final growing position — this is the most important rule for calabrese. Make stations 30cm apart in rows 45cm apart. Sow 3 seeds per station at 1cm depth. Thin to the strongest when seedlings reach 5cm. Net immediately. Sow a short row every 3 weeks for continuous harvest.

Suitable varieties: All varieties. The only reliable method for most UK conditions.

🪴 Modules (Early Start Only)

Modules can be used for February sowings to get an early start under cover. Sow one seed per module at 1cm depth on a cool, bright windowsill. Transplant at the 3-leaf stage — before roots fill the module. Handle the rootball with great care. Never allow to become pot-bound. This method carries higher bolting risk than direct sowing and should only be used for the earliest crops.

Suitable varieties: F1 varieties only for early starts. Not recommended from March onwards — sow direct instead.

06 Companion Planting

✅ Grow nearby

• 

  🌺 Nasturtiums

  Sacrifice plants — aphids and caterpillars go to nasturtiums first, protecting calabrese heads. Plant at the bed edges as a living trap crop.

• 

  🌿 Dill

  Dill attracts parasitic wasps and hoverflies that prey on cabbage white caterpillars and aphids. Plant at the margins of the brassica bed.

• 

  🥬 Celery

  Celery is said to deter the white cabbage butterfly. Interplanting with brassicas is a traditional kitchen garden companion technique.

❌ Keep apart

• 🍅 Tomatoes — Nightshades and brassicas compete strongly for nutrients. Keep in separate beds and rotate annually.
• 🍓 Strawberries — Brassicas suppress strawberry growth in close proximity. Maintain a clear gap of at least one bed width.
• 🌿 Fennel — Fennel root chemicals are allelopathic and inhibit calabrese and all brassicas.

07 Sowing — How To

Calabrese must be sown direct into its final position — transplanting almost always results in bolting or poor heads. Make stations 30cm apart, sow 3 seeds per station, and thin to the strongest.

1. 

   Prepare the bed

   Rake to a fine tilth. Tread the bed firmly — firm soil produces firmer, denser heads. Calabrese likes fertile, well-firmed ground. Rake in a balanced brassica fertiliser if the soil is light.

2. 

   Sow at correct depth

   Make stations 30cm apart in rows 45cm apart. Sow 3 seeds per station at 1cm depth. Water in gently. Do not sow too deep — 1cm is sufficient.

3. 

   Thin to one plant

   When seedlings reach 5cm tall, thin to the strongest at each station. Cut surplus seedlings at soil level rather than pulling — pulling disturbs the roots of the plant you are keeping.

4. 

   Net immediately

   Cabbage white butterflies will lay eggs within days of emergence. Net with fine insect-proof mesh immediately after sowing — do not wait until plants are up.

5. 

   Water in well

   Keep consistently moist from sowing through to harvest. A check in water supply causes the plant to rush to flower and produce a poor, loose head.

6. 

   Watch for the head

   The central head develops rapidly once the plant matures. Check daily — harvest while tight and dark green, before any yellow colouring appears on the florets.

Regional sowing timing

Region	Sow / plant	Harvest	Notes
Scotland & Far North	Apr–May	Jul–Sep	Sow direct April–May. Choose fast-maturing F1 varieties. Harvest July–September before autumn cold sets in. · Apr–May
Northern England	Apr–Jun	Jul–Oct	Sow direct April–June. Successional sowings give continuous supply. Harvest July–October. · Apr–Jun
Midlands & Wales	Mar–Jun	Jul–Oct	Sow direct from March. Wide successional window. Harvest July–October. · Mar–Jun
Ireland & Isle of Man	Mar–Jun	Jul–Oct	Sow direct from March. Wide successional window. Harvest July–October. · Mar–Jun
South & SE England	Mar–Jun	Jun–Oct	Longest window. March sowings under fleece possible. Harvest June–October — earliest sowings give June heads. · Mar–Jun
South Coast & SW	Mar–Jun	Jun–Nov	Earliest start in UK. March direct sowing reliable. Harvest June–October with side shoots extending into November. · Mar–Jun

08 Using a Propagator

Calabrese is best sown direct into its final position — root disturbance at transplanting almost always causes bolting or poor heads. If an early start is wanted before March, modules can be used but only up to the 3-leaf stage before transplanting. A heated propagator is not needed and not recommended — calabrese germinates well at cool temperatures (10–18°C).

09 Soil Requirements

pH

6.5–7.5

Best

Loam, Clay loam

Tolerates

Sandy loam

Avoid

Acid, Waterlogged, Poor sandy

10 Ongoing Care

💧 Watering

Water deeply 1–2 times per week rather than little and often. Inconsistent moisture is the main cause of loose, poor-quality heads and premature bolting. A good soaking every few days is far better than daily surface watering. Apply a mulch of compost around plants to retain moisture. In a dry summer, prioritise calabrese watering — it responds dramatically to consistent moisture.

🌱 Feeding

Rake in a balanced granular fertiliser before sowing. A nitrogen-rich liquid feed applied 4 weeks after thinning encourages rapid, leafy growth and a large, dense central head. Avoid overfeeding in the final 3 weeks before harvest — excess nitrogen can produce loose, open heads.

✂️ Harvesting

Cut the central head with a sharp knife while florets are still tightly packed and deep green — before any yellow colouring appears. Leave 10cm of stem. Side shoots will follow for several weeks; pick them every 2–3 days to keep the plant producing. The side shoots from heritage varieties like Waltham 29 and Di Cicco are particularly abundant and many growers consider them more flavourful than the central head.

11 Watch Out For

🐛 Insects & pests

• 🦋 Cabbage Moth Caterpillar — Wilting or collapse of the central growing point of cabbages and Brussels sprouts
• 🦋 Cabbage White Caterpillar — Yellow, ribbed, skittle-shaped eggs in neat clusters on the underside of leaves in summer
• 🐜 Aphids (Blackfly & Greenfly) — Curled, distorted, or stunted growing tips — aphids inject saliva that causes leaf curl to protect them
• 🐌 Slugs & Snails — Silver slime trails on leaves, soil, and pots — often the first sign before damage is found

🍄 Diseases to watch

• 🥦 Clubroot — Clubroot (Plasmodiophora brassicae) is arguably the most feared soil-borne disease in UK kitchen gardens. It persists in the soil as resting spores for up to 20 years — meaning a bed that becomes infected is effectively lost for brassica growing for two decades without extraordinary intervention. Crop rotation is the most critical preventive measure.
• 🔵 Downy Mildew — Downy mildew is caused by oomycetes (water moulds) and is completely unrelated to powdery mildew despite the similar name. It thrives in cool, wet, humid conditions and is most damaging in spring and autumn. Each host plant has its own specific downy mildew species. Lettuce downy mildew can destroy an entire bed within days in the right conditions.
• 🩶 Botrytis (Grey Mould) — Botrytis cinerea (grey mould) is the most ubiquitous fungal pathogen in temperate gardens — present in virtually every garden soil and on plant debris. It becomes a disease only when conditions favour it: cool, humid, poorly ventilated environments with damaged or senescent plant tissue. In a greenhouse in autumn it can destroy an entire tomato or grape crop.

Full identification and treatment advice is in the Pests and Diseases sections.

12 Storage & Preserving

🧺 Fresh Storage

Store unwashed calabrese in the fridge for up to 3 days. Wrap loosely in a damp cloth or place in an open bag to retain moisture without causing condensation. Home-grown calabrese deteriorates faster than supermarket broccoli — eat as soon as possible after harvest for the best flavour.

❄️ Freezing

Blanch florets for 2–3 minutes in boiling water, plunge into ice water, drain and freeze flat on a tray then bag. Keeps for up to 12 months. Texture softens slightly but flavour remains excellent. Frozen calabrese is ideal in stir-fries, soups, pasta, and cheese sauces.

🍳 Cooking a Glut

Roast at 200°C with olive oil, garlic, and chilli until edges char slightly — outstanding flavour. Also excellent in stir-fries, pasta dishes, and soups. Side shoots are best lightly steamed for 3–4 minutes and served immediately — they lose their texture quickly if overcooked.

13 Expert Tips

14 Common Mistakes

15 See Also

• 🔄 Crop Rotation
• ⬜ Cauliflower