Broccoli
Brassica oleracea var. italica
Broccoli for UK gardens comes in two main forms: calabrese (a summer-cropping annual with a large central head) and purple sprouting broccoli (a winter-hardy biennial producing multiple small spears). Purple sprouting broccoli is particularly valued for filling the hungry gap in late winter and early spring when little else is ready. Both prefer fertile, well-firmed soil and a sunny, sheltered position.
Key facts
- Family
- Brassicaceae (Brassicas)
- Category
- Leafy
- Sowing window
- Mar–Jun
- Sowing depth
- 10 mm
- Watering
- medium
- Frost sensitivity
- medium
- Days to maturity
- Calabrese: 80-100 days from transplant; purple sprouting: harvest Feb-April following year
- Harvest window
- Feb - Oct
Sowing notes
- -Sow in modules and transplant after 4-5 weeks
- -Calabrese types: sow March-June for summer/autumn harvest
- -Purple sprouting broccoli: sow April-June, overwinters, harvests Feb-April the following year
- -Keep well-watered during dry spells to prevent premature heading
Varieties
Early Purple Sprouting is the most popular purple sprouting broccoli for UK gardens, producing masses of tender purple florets in late winter and early spring when the garden is at its hungriest. It is very frost-hardy and reliably overwinters to deliver a heavy crop of tasty spears from February onwards. An essential brassica for year-round cropping.
Romanesco is a visually stunning brassica with lime-green, spiralling fractal heads and a nutty, sweeter flavour than standard calabrese. It is technically a broccoli-cauliflower intermediate and requires similar growing conditions - fertile soil and consistent moisture. Best harvested when the head is tight and fully formed.
Issues & threats
Wilting
EnvironmentalPlants are drooping or losing vigour. Most commonly caused by water stress but can also indicate root damage, vascular disease, or heat scorch. Identifying the cause quickly is important as some causes are serious.
Poor germination
EnvironmentalSeeds are emerging unevenly or not at all. Usually caused by soil temperature being too low, seeds sown too deep, poor seed-to-soil contact, or old seed stock.
Damping off
Fungal diseasePythium spp. / Phytophthora spp.
Young seedlings collapse at or just below soil level, caused by fungal pathogens that thrive in overwatered, poorly ventilated growing conditions. Can spread rapidly through a seed tray.
Yellowing leaves
EnvironmentalLeaves are turning yellow, which can indicate a range of problems including nutrient deficiency, overwatering, disease, or natural senescence. Identifying whether the pattern is upper or lower leaves, whole leaves or between veins, is key to diagnosis.
Stunted growth
EnvironmentalPlants are significantly smaller or slower to develop than expected. May be caused by poor soil, nutrient deficiency, root restriction, compaction, pest damage to roots, or disease.
Clubroot
Fungal diseasePlasmodiophora brassicae
A severe soil-borne disease causing grotesque swelling and distortion of brassica roots. Infected plants cannot take up water or nutrients effectively and typically collapse or die back. Spores survive in soil for up to 20 years. One of the most serious diseases affecting the brassica family.
Aphids
PestSmall sap-sucking insects that colonise soft new growth, leaf undersides, and growing tips. Most species reproduce rapidly and colonies can establish quickly in spring and early summer. Also vectors of several plant viruses.
Chewing damage
PestGeneral chewing damage from an unidentified pest, leaving holes or missing leaf sections. May be caused by caterpillars, beetles, or other insects. Inspect at dusk to identify the culprit.
Sap-sucking pests
PestGeneral sap-feeding pest activity causing weakened or distorted growth. May be caused by aphids, whitefly, scale insects, or other sucking insects. Inspect leaf undersides and growing tips to identify the pest.