How to grow winter squash

Val Bourne / 21 March 2013

Acclaimed gardening writer Val Bourne explains how to get the best results from winter squashes, plus read tips on storing squashes.

Winter squashes have firm chestnut-flavoured flesh that’s delicious roasted in the winter months, or made into a soup.

They are delicious and very nutritious, being rich in beta carotene, iron, vitamin C and potassium. Squashes also contain small traces of calcium, folic acid, and minute amounts of B vitamins.

Young children and babies adore them and they are one of the first baby foods recommended for weaning. They are considered one of the super foods and they are at their best in the depths of winter.

Despite all this, a lot of gardeners don’t grow them or eat them due to ignorance. Yet they are easy to grow in sunny positions where they can ramble a little.

When to plant

Sow winter squash seeds under glass in April, pointed side down, in potfuls of good compost.

Put young plants outside from mid-May onwards - after the fear of frost has gone.

Where to plant

The secret of growing good squashes is to plant them in rich soil in full sun. Each of my plants always has a barrow full of garden compost underneath - a bucket of muck is not good enough.

How to plant

Plant young squash plants outside from mid-May, but cloche them over night (preferably with a heavyweight plastic bell cloche) to boost growth and ensure a good crop.

Seeds can be planted outside in mid-June. Prepare the ground by watering thoroughly and sprinkling on blood, fish and bone. Make a mound 30cm (1ft) high and 60cm (2ft) wide and plant two seeds per mound.

When to pick

Harvest winter squash as late as possible and only cut once the skin has thickened and the stalk has become dry, and then store them until late November before starting to eat them. They are tasteless if eaten fresh because they need six weeks to a couple of months to develop the nutty, sweet flavour.

How to store

When you harvest winter squash try to leave a couple of inches of stem if you can and then store them upside down by slotting the stem through a wooden bench or the greenhouse staging.

Squashes stored upright tend to catch the moisture in the depression round the stalk and then they rot off more easily. Once in store they should keep for at least three months - so they make an excellent winter vegetable from early November until the end of January or February.

Winter squash varieties

Winter squash varieties vary from the traditional butternut squashes sold in the supermarket to the round, small pumpkin-shaped Japanese onion 'kabocha' squashes. Some varieties do much, much better than others.

Butternut squashes (even 'Sprinter' which was bred for the cooler British climate) tend to fail in poor summers. They need heat and sun to crop well so butternuts are always a gamble.

Japanese 'kabocha' squashes perform well in horrible British summers. The kabochas were introduced into Japan by Portuguese sailors travelling from Cambodia in 1541.

The Portuguese name for squash was Cambodia abóbora and this became shortened by the Japanese to kabocha. Japanese market gardeners, who are highly skilled in the art of vegetable growing, now raise squashes in roughly a hundred days - encouraged by the warm, wet Japanese summers. But I have never failed with them, whatever the weather.

The three best winter squash varieties to grow


An F1 hybrid kabocha type that resembles a small round pumpkin. It has a very sweet flavour and always does well for me. This is my top variety for flavour as well as performance.

‘Uchiki Kuri’

'Uchiki Kuri', also known as the Japanese Red Onion squash, is a bright orange sweet squash that I enjoy eating with my Sunday roasts. It is probably from Hokkaido in Japan - kuri is a Japanese term for squash.


This heritage French variety (which literally means small chestnut) is thought to have come from China originally. It produces teardrop-shaped fruits with a real chestnut flavour.

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