Brussels Sprouts
Brassica oleracea var. gemmifera
Brussels sprouts are a slow-growing winter brassica that needs the longest season of any common vegetable - often 9 months from seed to harvest. They develop over summer and autumn, producing their characteristic tight sprouts after the first frosts, which improve the flavour. Firm soil, deep planting, and staking are important as the tall plants are top-heavy and vulnerable to wind rock.
Key facts
- Family
- Brassicaceae (Brassicas)
- Category
- Leafy
- Sowing window
- Feb–Apr
- Sowing depth
- 10 mm
- Watering
- medium
- Frost sensitivity
- low
- Days to maturity
- 26-31 weeks from transplant
- Harvest window
- Jan - Dec
Sowing notes
- -Sow in modules and transplant in May-June - needs a long growing season
- -Firm the soil well at transplanting - loose soil causes root rock and loose sprouts
- -Stake tall plants in exposed sites
- -Frost improves flavour - do not rush harvest
Varieties
Noisette is a heritage open-pollinated Brussels sprout producing small, nutty-flavoured buttons after the first frosts. The name refers to its hazelnut-like flavour, which is considered by many to be superior to modern F1 varieties. It is a late-season variety cropping from December into February.
Trafalgar is a popular mid-season F1 Brussels sprout producing firm, well-flavoured sprouts with good resistance to blowing (opening up). It is one of the most widely grown varieties in UK home gardens for its reliability and consistently tight buttons. Cropping from October through to December.
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.