Butternut squash: growing, harvesting & preparing the butternut pumpkin

With its pear-like shape, beige skin and bright orange flesh, butternut squash is not hard to spot. Read on to find out how to grow your own butternut squash successfully at home!

Butternut squash is a delicious, versatile vegetable that is packed with nutrients. Because it keeps so well over winter, you can enjoy this winter squash long after the growing season has ended. Here are our top tips on growing, caring for and harvesting butternut squash in your veg patch.

Characteristics and origin of butternut squash

Butternut squash is an annual, herbaceous plant that originally comes from South America. Nowadays, the pumpkin, which belongs to a subgroup of the species Cucurbita moschata, has a number of varieties that are cultivated around the world.

As is common with courgettes (Cucurbita pepo) and other cucurbits (Cucurbitaceae), the butternut squash plant forms large, green, heart-shaped leaves with fuzzy to rough hairs and silvery veins. The leaves are also often speckled with silvery-white spots. The plant’s shoots grow tendril-like above the ground, and can climb up supports. And its funnel-shaped, orange flowers are not only beautiful but edible!

However, the tastiest part of a butternut squash plant is its fruit. Butternut squash fruits are light yellow to beige and elongated, pear- or peanut-shaped. They have thin skin that contains melon-scented, deep orange flesh and only a few seeds. Unlike the spaghetti squash (Cucurbita pepo), this pumpkin is not fibrous even after cooking, but soft with a mildly sweet taste. The butternut squash, also known as butternut pumpkin or gramma, is probably named after its buttery, tender, nutty flesh.

Best butternut squash varieties for your garden

Butternut squash is already its own subgroup of winter squash. However, within this subgroup, there are several varieties.

• ‘Butterfly F1’: Italian variety with heavy, 3 to 4kg, slightly ribbed fruits. This hybrid variety grows quite compact and ripens from the end of September.
• ‘Early Nutter F1’: High-yielding hybrid variety with slender fruits that weigh about 1.4kg. The fruits are ready for harvest about 90 days after pollination.
• ‘Honeynut’: Ideal pumpkin for one to two people, as the fruits only reach just under 0.5kg. The skin is light yellow to light beige in colour. Inside there are very few seeds and lots of flesh.
• ‘Ponca’: American, high-yielding butternut variety with a weight of 0.5 to 1kg. The many small fruits ripen reliably even in cooler summers.
• ‘Tahiti Melon’: Butternut squash variety with a round body and uniquely long necks, almost like a swan. This variety has a particularly sweet, almost melon-like taste.
• ‘Waltham’: Pear-shaped butternut squash with light beige skin and fruits weighing up to 2kg. Ripens late from the end of September to October.

Planting butternut squash

If you want to grow your own butternut squash, begin by sowing the seeds on a windowsill in spring. This can be done from April, once it is warm enough indoors. To help the butternut squash seeds germinate, it is best to start with a growing medium. Our Plantura Organic Herb & Seedling Compost is a great choice. It is has less nutrients than standard plant soil, which forces the seedlings to develop a larger root system.

Cover your seeds with soil so that they are about 3cm deep. Keep the seeds evenly moist and warm – 20 to 24°C is sufficient. After about one to two weeks, the seeds will germinate. Move them to a sunny spot by the window.

Instead of buying butternut squash seeds, you can collect them from your own fruit. Once dry, these seeds will be ready to sow next year. Do note, however, that pumpkins are cross-pollinators. This means that bitter tasting, poisonous pumpkins may grow from your seeds. Even seeds you purchase from a garden centre, and fruits from the supermarket, can contain bitter, poisonous substances. As such, look out for bitter tasting pumpkins, and do not eat them!

As soon as your butternut seedlings form their first heart-shaped leaves, transplant them into larger pots with nutrient-rich potting soil. Gradually harden off the plants from the beginning of May, before planting them outdoors, once the threat of frost has passed. Be sure to keep at least one metre between the plants. For wider spreading varieties, allow about two square metres per plant.

The ideal place to grow a butternut squash is next to your compost heap. However, if this is not possible, look for very nutrient-rich, well-draining soil and lots of sun. You can always improve your soil, by mixing in your own compost, or using our Plantura Organic Enriched Compost. This nutrient-rich compost is ideal for any heavy-feeding vegetable. It is also packed with organic matter, which promotes a healthy soil life.

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Tip: One tried and tested way of growing squash is the “milpa bed” or “three sisters” companion planting method, where corn (Zea mays), beans (Phaseolus vulgaris) and squash are grown together. In this way, each vegetable benefits from the properties of the other two.

Pruning, fertilising and caring for butternut squash

Pumpkin plants need a lot of water to grow, so be sure to water your plants often, especially after planting and during dry spells in summer. To prevent disease, like mildew, always water directly into the soil and not onto the plant’s large leaves. And do avoid water stagnation. Lukewarm rainwater or untreated tap water are ideal for watering butternut squash.

Like tomatoes (Solanum lycopersicum), butternut squash plants are heavy feeders, and require a lot of nutrients. As soon as the first flowers appear, begin fertilising your butternut squash. If you are looking to eat the fruit, use a plant-based fertiliser, such as our Plantura Tomato Food. This is a long-lasting fertiliser that releases its nutrients slowly over a period of three months.

For the tastiest butternut squash crop, it is worth cutting the shoots from about five fruit sets per plant. This will prevent excessive numbers of fruits. Alternatively, pick the five most promising pumpkins early on, and remove all other fruiting sprouts and their side shoots.

Harvesting butternut squash

Harvest your butternut squash in autumn, between September and October. Be sure to harvest all of your fruits before it becomes chilly. Sun-loving butternut squash does not tolerate frost.

Here is how to tell when your butternut squash is ripe:

• Sounds hollow when tapped on the hard shell,
• Very woody, brown fruit stalk that is difficult to cut through,
• Variety-dependent colour achieved, usually light yellow with no streaks.

A soft stem is a sign that the butternut squash is still unripe. To store pumpkins, leave the stem attached to the fruit. This will prevent rot from entering the wound.

Can butternut squash ripen after harvesting?

Like all pumpkins, butternut squash can ripen after picking. This is especially useful if you have harvested your vegetables early due to frost. To facilitate its ripening, store your pumpkin in a warm (15-20°C), dry location, preferably on a dry surface such as straw. Turn your butternut squash regularly to avoid rotting and bruising and to allow air to circulate around the fruit.

Storing and preserving butternut squash

Butternut squash can be stored at a slightly cooler temperature: 15°C is ideal – anything colder than 10°C is dangerous. An air-dry environment will prevent the winter squash from rotting, and the fruits should not touch one another. We suggest hanging your fruits individually in nets, or storing them in boxes or on straw. In this way, they will keep well into next spring.

Alternatively, preserve your fruit by cutting it into small pieces and freezing it. Boiled down and stored in salt water, butternut squash will keep for up to a year. Similarly, you can cook the butternut squash into a dish, like soup, and then freeze the dish.

Cooking butternut squash

Butternut squash is low in fat, and extremely healthy. The vegetable is loaded with nutrients, like beta-carotene, vitamin A and vitamin C, which have a positive effect on vision, skin and hair, and even its seeds are healthy and edible. Simply season the seeds and roast them in the oven for a delicious snack!

There are countless ways to prepare butternut squash – get creative! Why not try making a delicious butternut squash soup, roasting them with herbs and spices or even cooking them into a nutty, buttery tasting pasta sauce.

Can I eat the skin of butternut squash?

Although butternut squash skin is edible, it is usually removed. It is quite hard and does not soften well even when cooked, so many people find the texture unpleasant.

Can I eat butternut squash raw?

Edible pumpkins like butternut squash can be eaten raw. However, remove the skin first.

Besides edible pumpkins, like butternut squash, there are also ornamental pumpkins that are not suitable for eating. Here is our guide to edible and poisonous pumpkin varieties.