how to plant, grow & care for squash

complete growing guide

There’s so much to love about squash. The sheer variety of shapes, colours and flavours means there are endless possibilities for your vegetable garden and your plate. They range from huge pumpkins to small ‘Patty Pan’ varieties, and the colours also vary from mottled greens and yellows to vibrant sunset shades. 


Some of my favourites are exceptionally decorative, such as squash ‘Uchiki Kuri’, which climbs up and over frames and produces lovely orange fruits with a sweet taste and waxy texture. Others are stalwarts in the kitchen, including the silver-blue skinned pumpkin ‘Crown Prince’, which always excels in taste trials and stores exceptionally well for up to a year. I also love the tiny and tasty pattypan ‘Sunburst’ and the huge and handsome pumpkin ‘Marina Di Chioggia’ – it’s like a living sculpture in the garden.


Browse our range of squash seeds and seedlings, the seedlings will arrive ready to plant out in your garden.

details

  • Common name Squash
  • Latin name Cucurbita pepo / Cucurbita moschata
  • Type Half-hardy annual
  • Height 60cm (2ft) to 90cm (3ft) – some can trail/climb up to 4.5m (15ft)
  • TLC rating Easy
  • Aspect Full Sun
  • Spacing 60cm (2ft) to 2m (6½ft)
  • Yield 3 to 4 month harvest
  • Suitable for pots Yes, compact varieties
  • Grow in a greenhouse No

calendar

JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Sow Under Cover/Plant Indoors
Direct Sow/Plant Outdoors
Flowers/Harvest

how to grow squash

where to grow squash

Soil type: Squash thrive in moist, fertile soil. Add compost or well-rotted manure to enrich the soil and help retain moisture.


Aspect & Position: A sunny spot is essential for growing squash.


when to plant squash

Seeds should be sown undercover in March, April and May. Seedlings can be planted out after the risk of frost has passed in late May, June and July.


how to plant squash

sowing squash seeds

Check instructions for each variety before sowing, but as a general rule, you can sow squash seed undercover in March, April and May. You can direct sow after the risk of frost has passed in May or June.

To sow undercover, sow 1-2 seeds to a 9cm (3½in) pot filled with peat-free compost. Push the flat seed on its side into the compost about 2½cm (1in) deep. 

For the best chance of germination, place somewhere warm with a minimum temperature of around 15ºC (59ºF). Thin out the weakest seedling.

If sowing directly outside, sow 2 or 3 seeds at a depth of 2½cm (1in). Once the seedlings are growing, thin out to leave the strongest one following the spacing indicated on the packet. 

squash seedlings

Indoor-raised seedlings will require hardening off before being planted out. Once they have 5-6 leaves, gradually acclimatise seedlings to outside conditions by leaving them outside during the day in a bright, sunny spot and bringing them back in, or covering with horticultural fleece, in the evening. 

Ensure seedlings are spaced well apart – trailing winter squash and pumpkins in particular have a sprawling or trailing habit and their spread can reach up to 4.5m (15ft).

Trailing squash like a strong support to clamber over and some can even be grown up a trellis or archway.

growing squash in a pot

It is possible to grow squash in growbags or containers, but ensure they are a minimum 45cm (18in) in diameter. Allow one plant per container or two per growbag and make sure to water and feed the plants throughout the growing season. Trailing squash will need a strong support to clamber over.


how to care for squash

watering

Keep squash well watered and avoid the plant becoming dry – avoid getting leaves wet while watering. Keep an eye on squash growing in containers as these will dry out faster than those in the ground. To improve moisture retention in the soil, mulch the surface well.

fertilising

Feed every fortnight with a high potash liquid fertiliser, such as Organic Tomato Fertiliser with Seaweed once the plants are flowering.

training

Winter squash and pumpkins need space to clamber and scramble, as well as strong supports. The most vigorous climbers will even welcome a trellis or arch. 

pruning 

The absolute key to a good harvest is to pinch out the growing tips of all the plant shoots in mid-August and to keep doing so. This stops plants putting on triffid-like, leafy growth and forces them to focus energy on the developing fruits.

Without pinching out, some just drop their flowers or immature fruit in favour of shooting out like a giant squid. Keep them contained and you'll have many more fruits to harvest.

harvesting

This depends very much on the variety. Summer squash can be harvested regularly from July onwards, like courgettes, while winter squash and pumpkins usually develop only a few, large fruit which should be left on the plant to mature until the end of summer.
 
Make sure to pick winter squash and pumpkins before the frosts arrive. And when harvesting, cut them with 10cm (4in) of stalk attached to the fruit.

Most varieties need to be cured for at least a week before you store them. Leave them on a sunny windowsill before storing somewhere dry and frost free. Then they can last for several weeks or even months.

seasonal checklist

spring

  • Sow seeds undercover ready to plant out once the risk of frost has passed.





summer

  • Feed and water squash plants regularly to encourage fruit. 
  • Summer squash will be ready to harvest from July.
  • Mulch around plants to help with the moisture retention.

autumn

  • Winter squash and pumpkins will be ready to harvest from late August.

winter

  • Start planning out which squash you would like to sow in spring.

pests, diseases & common issues

powdery mildew

Squash can suffer from powdery mildew, which is a fungal disease that shows up as a white powdery coating on the foliage. 
Remove any affected leaves and try an organic solution such as homemade comfrey tonic to keep mildew at bay. Keep the soil moist and move plants to a cooler location if growing in containers. And remember to avoid getting leaves wet while watering.

why are my squash plant leaves turning yellow?

If the yellowing is severe, it could be a sign of verticillium wilt – a fungal disease that infects the plants from the roots. Signs include wilting leaves, yellowing leaves and a dieback. The fungal disease lives in the soil, so you need to remove the plant with any soil attached to the roots and dispose of it.

why are there white spots on my squash plant leaves?

A white, powdery coating usually indicates powdery mildew. 

why is my squash rotting on the plant?

Irregular and under watering can lead to blossom end rot, which is a calcium deficiency in the fruit and shows up as a black, flattened bottom on the fruit. Consistent watering will help ensure future fruits are healthy. 

If it’s not blossom end rot, it could be that the squash plant is too small and weak to support the full development of the fruit. It could also be a sign that the plant is stressed – ensure you water and feed your squash regularly.


frequently asked questions


when should you plant squash in the UK?

Seeds should be sown undercover in March, April and May, and seedlings can be planted out after the risk of frost has passed in late May and June. You can also sow seed direct in May and June.


how many squash do you get per plant?

For butternut squash you can expect 5 or 6 fruits per plant through the growing season, for some larger squash and pumpkins you may only get 2 to 4.


when is the best time to plant out squash?

Seeds should be sown undercover in March, April and May. Seedlings can be planted out after the risk of frost has passed in late May and June.


how deep should you plant squash?

Sow squash seed at a depth of about 2½cm (1in) deep, with the seed sown vertically. Then plant out at the same level as they were in the pot.


how far apart should you plant squash?

Sow 1-2 seeds to a 9cm (3½in) pot and thin the weakest seedling. Ultimate spacing will depend on the variety of squash, but be mindful that some varieties have a trailing habit and their spread can reach up to 4.5m (15ft).


should you remove dead leaves from squash plants?

Yes, dead leaves can be removed from squash plants.


can you over water squash plants?

Consistent watering is key. Under watering can lead to various problems including blossom end rot, but over watering can lead to powdery mildew. 


do squash plants come back every year?

Squash is an annual – sow new seed each year.


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squash recipes

Find out how to cook your home-grown produce and get inspiration for tasty meals with our seasonal recipes:

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