How to Grow Romanesco
Brassica oleracea var. botrytis
Romanesco is a stunning fractal brassica that produces lime-green spiralling heads. It needs rich, firm soil, consistent moisture, and cool growing conditions without temperature shocks. Start seed indoors in spring, transplant carefully to avoid check, and keep well-watered and fed. Net against pigeons and butterflies. Harvest when heads are tight and well-formed. More demanding than cauliflower but worth the effort for its unique appearance and nutty flavour.
When to Start
Sow indoors 5 weeks before last frost, or direct sow outdoors after frost risk has passed and soil reaches 8°C.
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Growth Stages
Approximate days from start
Care Essentials
- Feed with a nitrogen-rich fertiliser when transplanting and again when heads begin to form. Brassicas are hungry plants.
- Romanesco is more temperamental than cauliflower — it needs consistent conditions without temperature shocks. Avoid transplant stress and keep evenly moist.
Growing Conditions
- Min. soil temperature
- 8°C+
- Germination temperature
- 10–25°C
- Sow indoors
- —
- Transplant out
- —
- First harvest
- —
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Spacing & Planting
| Plant spacing | 60 cm |
| Row spacing | 75 cm |
| Sow depth | 1.5 cm |
| Mature height | 60 cm |
| Mature spread | 60 cm |
Large plants that need generous spacing for good head development. Do not crowd.
Pests & Diseases
Pest Cabbage White Butterfly
Identification: Green caterpillars on leaves, large ragged holes, frass visible
- Fine mesh netting (best prevention)
- Hand-pick caterpillars
- Encourage parasitic wasps
- Bacillus thuringiensis (Bt) spray
Pest Wood Pigeons
Identification: Stripped leaves, torn foliage, bird droppings nearby
- Netting or cage protection
- Bird scarers
Disease Clubroot Plasmodiophora brassicae
Symptoms: Wilting in warm weather despite moist soil. Swollen, distorted roots when pulled up.
Treatment: No cure. Remove and destroy affected plants. Do not compost.
Prevention: Lime soil to raise pH above 7.2. Rotate brassicas on a 4-year cycle. Start plants in clean compost in pots.
Growing Conditions
| Min. soil temperature | 8°C |
| Germination temperature | 10–25°C |
| Base growth temperature | 5°C |
| Min. daylength to start | 10h |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Romanesco?
- Plant Romanesco 60cm apart with 75cm between rows.
- When can I harvest Romanesco?
- Romanesco is ready to harvest approximately 80 days after transplanting.
- Is Romanesco frost hardy?
- Romanesco is classified as Half Hardy.
