How to grow butternut squash

Freshly harvested butternut squash
Image: Squash 'Hunter' F1 Hybrid (Winter) - Seeds from Thompson & Morgan

Butternut squash is the king of the autumn squashes for its sweet flavour and bright orange flesh. Versatile in the kitchen, it also has an excellent shelf life for winter storage. Here, trained horticulturist Sophie Essex explains how to grow your own butternut squash from seed.

Explore our full range of pumpkin, squash & courgette seeds to find the best varieties for your garden. 

How to sow butternut squash seeds

Organic butternut squash seeds are chemical-free
Image: Squash 'Waltham Butternut' (Winter) - Organic Seeds from Thompson & Morgan

Sow each seed individually in a small pot filled with sieved multi-purpose compost. Clean yoghurt pots are a good alternative to buying new plastic pots. Push the seed about 1 inch deep into the compost, narrow side up. Make sure your soil is nice and moist to prompt germination.

Place your pots on a tray covered with a clear plastic bag and set on a warm windowsill. When you see small shoots appearing, remove the bag but keep the pots in the warmth, turning occasionally.

As the risk of frost passes in May, harden the young plants off for a week or so. Young butternut squash plants have large leaves and thick stems, but treat them delicately, handling them only the leaves as you transfer them to the garden or allotment. 

Alternatively, sow butternut squash seeds outdoors in May and June in soil that has been pre-warmed by a cloche. Sow two seeds per station and thin to the strongest seedling if both seeds germinate.

Where to grow butternut squash

Butternut squash seedlings quickly grow new leaves
Image: Denis Pogostin/Shutterstock

Grow your butternut squash in a sunny spot in rich, free-draining soil. Add plenty of compost and well-rotted horse manure to the soil when preparing the planting area, and rake well to remove any clumps or stones. If you don't want to turn over the whole plot, you can prepare individual planting pockets, 45cm (18") wide and deep, spaced 1m (3ft) apart to plant your butternuts into.

Label your butternut squashes as you plant them – squashes, courgettes and cucumber plants look very similar when they’re young! Water each plant well after planting.

If you want to make best use of the space in your vegetable patch, double up by growing butternut squash in and around your sweetcorn. Add climbing beans to scramble up the sweetcorn and you’ll have all of the ‘three sisters’ companion planting trio. No space left on the veg patch? Try growing butternut squash directly on the compost heap! The long vines will scramble over the compost, thriving on all the nutrients it contains.

How to grow butternut squash in pots

Butternut squash are a great option for patio pots
Image: A. Houdayer/Shutterstock

If you don’t have a big veg patch or allotment, you can still grow butternut squash in a large container. Choose a heavy-bottomed, wide pot with a minimum diameter and depth of 45cm (18in). Remember that your squash plants will trail, so allow plenty of space for the vines to spread. Use a rich compost and mulch around the base of each plant.

Another easy way to grow butternuts is using a grow bag. Plant up each grow bag with two plants, and make sure you water regularly to prevent the compost from drying out. 

Do away with frequently feeding your container plants through the season by adding incredicrop® to your compost at planting time. Providing 7 months coverage, it will last the entire life of these long-season plants.

How to care for butternut squash

Butternut squash fruits have thin skins and rich, creamy flesh
Image: Kolpakova Svetlana/Shutterstock

As your squashes begin to sprawl and tangle around each other, it can be hard to locate the centre of each plant for watering. I like to set a cane by each plant when planting out, to act as a marker for later in the season.

If you find that you have too many male flowers, nip them off to focus the plant’s energy on producing female flowers. Butternut squash flowers are an edible delicacy in their own right - stuff them with cream cheese to bake in the oven or dip them in tempura batter and flash fry. Both go well with a sweet chilli dip.

As the fruits begin to swell, place a handful of straw underneath to prevent rot. When you come to harvest, cut the fruits off with 2cm of stem attached and place in a warm space out of direct sunlight to dry for a few days. When they’re dry and the skins have hardened, store your squashes in a cool, dry space until you need them. 

Best butternut squash varieties to try at home

This early variety has bright orange flesh and a patterned skin
Image: Butternut squash 'Inca Gold' F1 from Thompson & Morgan

British-bred butternut squash ‘Hunter’ F1 is a popular, reliable variety for growing at home in the UK. The plants each produce 4 or 5 long, pear-shaped fruits that reach a weight of up to 1kg with good sweet flesh and small seed cavities. 

If you’re an organic gardener, go for squash 'Waltham Butternut' which has been developed without the use of chemicals. Expect to harvest around 4 tan-skinned squashes per plant in early autumn, each with a long pear shape and small seed cavity. 

For something different, try the earliest butternut squash 'Inca Gold' F1. This special variety has the sweetest bright orange flesh inside orange and green patterned skin. If you’ve previously struggled to get your butternuts to fully ripen, this is the squash variety to try. The delicious, sweet fruits can be ready as early as August.

We hope you’ve found our guide to growing butternut squash at home helpful. If you want more helpful resources, you’ll find all of our butternut, pumpkin and squash growing advice over at our dedicated hub page.