Squash Growing Guide
Squashes are eye-catching and productive plants, producing fruits in a wide choice of colours, shapes, sizes and flavours. They range from large sprawling vines to more compact 'bush' plants. They are closely related to pumpkins and courgettes, known botanically as cucurbits, mainly varieties of Cucurbita moschata, C. maxima or C. pepo. They are grown for their edible fruits, categorized into summer and winter types.
This guidance applies to the crop in general. Individual varieties and local conditions can differ.
Planting information
Squashes are best started from seed indoors in spring, from mid- to late April. Sow seeds on their side, 1.3cm (0.5in) deep, in 7.5cm (3in) pots or modular trays of peat-free multi-purpose compost, one seed per pot/module to minimize root disturbance. Keep at 18–21°C (65–70°F) in a heated propagator or on a warm windowsill. Water regularly and keep in good light. Seeds can also be sown outdoors in late May or early June, 2.5cm (1in) deep, two or three seeds into each prepared site, then thinned to the strongest seedling. Warm the soil with a cloche or fleece before outdoor sowing. Plant indoor-raised or bought plants outdoors after the last frost. First, harden them off to acclimatize them to outdoor conditions. Plant into prepared ground, taking care not to disturb roots. Firm gently and water well. Space bush varieties 90cm (3ft) apart and trailing varieties 1.5m (5ft) apart. Summer squashes can also be planted one or two per growing bag or one in a container at least 45cm (18in) wide, filled with peat-free multi-purpose or soil-based compost.
Harvesting information
Summer squashes produce fruit from mid-summer onwards until the first frost. Harvest their fruits when small and tender with a soft skin; regular picking encourages further fruit production. Winter squashes can be harvested and used immediately or stored for many months. Keep winter squash fruits on the plant as long as possible for best flavour, but pick before any frosts. Cut fruits from the plant with at least 10cm (4in) of stem still attached to prevent rotting during storage.
Storage information
For storing winter squashes, allow fruits to fully ripen on the plant. After harvesting, lay them out in the sun for an additional one to two weeks, either outdoors or in a greenhouse, to harden the skin. Bring them indoors before the first frost. Store fruits in a well-ventilated place at 10–15°C (50–60°F), spaced out so they do not touch. Depending on the variety, winter squashes should keep for three months or more. Regularly check for signs of deterioration or rot.