Squash
Cucurbita maxima / moschata
Winter squash and butternut types are trailing plants that spread widely but reward patience with heavy, long-storing fruit. Unlike courgettes, they are left on the plant to fully mature before harvest in autumn, developing hard skins that allow them to keep for months in a cool, dry place. They need a long growing season and warm conditions to set fruit - cloches or fleece help in marginal seasons.
Key facts
- Family
- Cucurbitaceae (Cucurbits)
- Category
- Fruiting
- Sowing window
- Apr–May
- Sowing depth
- 30 mm
- Watering
- medium
- Frost sensitivity
- high
- Days to maturity
- 90-110 days from transplant
- Harvest window
- Sep - Oct
- Storage
- Cool, dry, frost-free place after curing
- Storage duration
- 3-6 months depending on variety
Sowing notes
- -Sow indoors in April; direct sow outdoors in May after frost risk has passed
- -Winter squash types (butternut, Crown Prince, etc.) - different from courgette
- -Trailing types need space (1.5-2m spread); compact bush types available
Varieties
Butternut is the most popular winter squash for UK gardens, producing tan-skinned, pear-shaped fruits with sweet, deep-orange flesh. It is more compact than many squashes and stores exceptionally well - up to 6 months in a cool, dry place. It needs a warm season to ripen fully and benefits from starting indoors in April.
Crown Prince is a UK favourite, producing distinctive blue-grey, drum-shaped fruits with vivid orange flesh and an outstanding sweet, nutty flavour. It keeps exceptionally well and is considered by many to be the finest-tasting winter squash available. The large fruits can weigh 3-5 kg and require a long, warm growing season.
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.
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.