Top of The Crops - Squash

Squash Growing Guide

Squash is a lovely crop that comes in a variety of sizes, shapes, and colours. They can be used in many recipes from soups to hearty stews and are a worthy crop for any garden or polytunnel. As well as being versatile, they are relatively easy to grow. Despite taking up a lot of room, certain types of squash can store well for months – making them a great crop to grow and harvest for use in the kitchen all year round.


How to grow squash

Although they take up a lot of space, the pay-off is always worth it for both domestic and commercial growers. Squash has a range of summer and winter varieties, meaning it can be grown and harvested across different growing seasons – which can be extended even further when grown in a polytunnel.


Squash varieties

Different varieties call for different treatment, and you should take time to note which types you are planning to grow before you go ahead and prepare your garden.

Winter squash generally grow on vines and need a lot of space. Given the right conditions, they can (and will!) take up a large section of your garden or polytunnel. Winter squash varieties include Acorn, Spaghetti and Butternut squashes.

Summer squash are bushy and can grow to be quite large. Though they take up space, they won’t take up as much of your garden as winter vine varieties do. Popular summer squash include Courgette, Crooked-neck and Straight-neck varieties.


Seed sowing

Easy to grow, squash can be started outdoors or indoors from seed. Indoor sowing in pots is recommended for unpredictable or colder climates (we would recommend this for UK growers), as they do better in warm soil. However, they can also be started outside and will thrive within a polytunnel or greenhouse.



If you are starting your squash outdoors, sow in late May / early June[i]

  1. Sow 2-3 seeds 1 inch deep in your soil
  2. Cover with a cloche hoop, plastic or jars (a mini polytunnel would come in handy here)
  3. Allow to germinate for a few weeks
  4. Choose the strongest seeds for planting
  5. Consider planting within a walk-in fruit cage to keep the young seedlings safe

When sowing within a polytunnel or greenhouse, we would advise using a heater to keep your squash at an optimum temperature.



If you are starting indoors, you can sow your squash seeds as early as April or May and will be able to plant them as the weather gets warmer in June/July.

  1. Sow your seeds 1.5cm/1 inch deep into your soil

  2. Sow 3-4 weeks before planting
  3. Use 10cm (4in) pots[ii]
  4. You can sow 2/3 seeds per pot, make sure they are amply spaced apart
  5. Place your pots in trays of water to ensure they are watered from below
  6. Place somewhere warm. The soil should reach around 21c to ensure germination takes place

You could also sow into seed trays and transfer them into pots once the roots begin to grow but sowing directly into pots works best as there is less root disturbance involved.



Planting squash is relatively simple once you have the basics covered. Location, soil quality, whether you are planting within a container or directly into the soil – each aspect will affect the speed and quality of your squash growth.

Transplanting seeds – Once your seeds have germinated and are ready for planting, you can get prepared to transfer them. Hardening the plants off is an extremely important step in ensuring your plants don’t fail early on. To do this, move them outside during the day for about a week before planting but never leave them out overnight, especially when there is a risk of frost. You should avoid disturbing the roots as much as possible as they will be quite fragile at this stage.

Soil Quality – As with many crops, free-draining, rich soil[iii] that has been prepared with plenty of nutrient-filled fertiliser is best for squash growth. The soil needs to be kept sufficiently moist, so don’t allow your growing patch to dry out whilst waiting for seeds to be ready for planting.

Mulching your soil will help to maintain soil moisture, as well as reducing the risk of weed growth.

Location - Wherever you choose to plant your squash, it’s important to think about space, make sure that you keep 1-2m between plants[iv]. Trailing varieties such as ‘Crown Prince’ need at least 1.2m (4ft) between plants. Planting pockets should be around a spade's depth and width and will help to feed these hungry plants. Now, where to plant them? Squash will only grow well in warm soil, which you should consider when choosing your planting location. We would recommend covering your squash with plastic/polyethene to maintain a suitable soil temperature (especially on colder days), and to make sure you choose a spot that sees a lot of sunlight.

How to plant – Make sure to plant your squash on a mound or ‘hill’. Each mound should be 3-4 feet apart (or more or less depending on the variety), and you should stick to sowing 4-5 seeds per mound. As the plants start to flower and the fruit develops, you can thin this out to 2-3 plants per mound to ensure the healthiest plants get the space they need to grow[v].

Support – To save space, it is best to support vining squash and pumpkins on trellising or some other form of support rigged to the crop bars in your polytunnel.



Once the tricky part is out of the way, you need to keep your squash well maintained. Keep an eye out for pests, bugs and signs of damage or diseases such as blight and blossom end rot[vi]. Water your squash once a week, ensuring they get about 1inch of water per week. The soil they are in should be moist 8-12 inches below the surface at all times. Alter your watering patterns depending on the weather.

To ensure fruits that reach the ground do not rot, place something beneath them (tiles generally work best for this purpose.) Make sure to cut back foliage as and when needed so that sunlight can reach the plants and ripen them faster.



Summer squashes, such as small patty pan squashes, are treated like courgettes and are harvested while the fruits are still immature, in the summer and early autumn. In contrast, winter squashes and pumpkins are left to mature on the vine and harvested before the first frost strikes.

When squash reach their harvesting stages, the fruit can change quite quickly, so it’s important that they are monitored daily for signs that they are ready for harvest.



When should you sow, plant, and harvest your squash?

Sowing Time

April / May

Planting Time


Harvesting Time

Squash should be harvested when ready, growing time can be anywhere from 60-110 days[vii]



The wonderful thing about squash (particularly overwintering squash) is that they store very well. Curing squash allows certain varieties to last until the following Spring. To cure squash after harvesting, leave them out to ‘cure’ in the sun for 7-10 days after harvest. This allows the skin to harden and protect the innards of the fruit. If you cannot leave yours outside, leaving them on a sunny windowsill can work well. Vitally, don’t leave them outside if there’s any chance of frost.

Keep at temperatures of 10-12c and ensure you do not stack or let the squash touch each other. Each squash varieties storage time is different so make sure you keep an eye on them.


Give squash growing a go

Follow the above advice to grow your squash this growing season. Deliciously versatile, squash go down a treat in any home!



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Earth Easy, n.d. Growing Squash: How to Plant, Grow, Harvest, and Store. [Online]
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Morgan, T. &., n.d. How to grow butternut squash. [Online]
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RHS, n.d. Squash. [Online]
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Tilley, N., n.d. Tips for Growing Squash. [Online]
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