How to grow squashes

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, so there are types to suit all gardens. 

Grow an array of squashes for tasty harvests and a splash of colour on your veg plot

Moving a plant from one growing position to another, often from a pot to its final spot in the garden.

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Choose a warm growing site in full sun, with rich, moisture-retentive but not waterlogged soil. Squashes also need plenty of space – even the more compact bush varieties can easily spread to 90cm (3ft) across.  

Before sowing or planting outdoors, prepare the ground where each squash plant will grow. Make a hole about 30cm (1ft) wide and deep, then fill it with a mix of soil and organic matter, such as home-made garden compost. Alternatively, if you’re practising no-dig, mulch the surface and sow or plant into the mulch. Space each sowing/planting site at least 90cm (3ft) apart for bush plants and 1.5m (5ft) for trailing plants. 

You can also plant summer squashes in growing bags and large containers of peat-free multi-purpose or soil-based compost.

Squashes are usually sown indoors in spring, for more reliable germination and to give them a head start, then planted out after the last frost. They can be sown outdoors too, but not until late May or early June. Germination outdoors may be less reliable if temperatures dip, and the seedlings are vulnerable to slugs and snails, as well as poor weather.

You can plant indoor-raised or bought plants outside after the last frost. But first, harden them off to gradually acclimatise them to outdoor conditions. Plant young squash plants into prepared ground (see above), taking care not to disturb the roots. Firm them in gently, then water well. Space bush varieties 90cm (3ft) apart and trailing varieties 1.5m (5ft) apart.

You can also plant summer squashes in growing bags or large containers in a sunny, open spot. Plant 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. Make sure there is plenty of space around the container, to ensure good air circulation and allow plants to spread. Overcrowded conditions can encourage fungal diseases.

If you have plenty of space, trailing types can be left to sprawl over the ground, but if you need to limit their spread, you can train the stems around in a large circle, inserting short canes to hold them in place. You can also simply cut off any stems that stray beyond their bounds.

Trailing squashes can also be trained up supports – such as an arch, pergola, wigwam of hazel stakes or a strong trellis – but make sure they’re large and sturdy enough to carry these vigorous plants and their crop. You may need to use netting to support individual heavy fruits, so smaller-fruited varieties may be more suitable.
 

With winter squashes for storing, let the fruits fully ripen on the plant – the riper they are when harvested, the better they’ll keep. Then lay them out in the sun for an additional week or two, either outdoors or in a greenhouse, to harden the skin, which also helps to ensure they store well. Make sure they are safely inside before the first frost.

Then store the fruits in a well-ventilated place at 10–15°C (50–60°F), spaced out so they don’t touch. Depending on the variety, winter squashes should keep for three months or more. Check them regularly for any signs of deterioration or rot.

Squashes are tender plants, so are susceptible to cold and frost. They can also be affected by various diseases, and slugs and snails may eat young plants – see Common problems below for more details.