Growing Winter Squash

How to Plant, Grow, Harvest, and Cure Winter Squash

Butternut Squash on Vine
DLeonis/Getty Images

Growing winter squash requires some patience, but their delicious fruits are well worth the wait! Learn how to plant, grow, harvest, and cure winter squash at home.

About Winter Squash

Winter squash are harvested in autumn after or just before their fruits reach full maturity. This leaves their skin inedible, but gives them a longer shelf life than summer squash (some varieties are capable of keeping through the winter—hence the name “winter squash”).

Winter squash varieties include pumpkins, butternut squash, Hubbard squash, spaghetti squash, delicata squash, and acorn squash, among others!

Because winter squash require a long growing season (generally from 75 to 100 frost-free days), you’ll need to plant them by late May in northern locations to early July in extremely southern states.

Planting

When to Plant Winter Squash

  • Like summer squash, winter squash do best when seeds are sown directly into the garden. However, if your growing season is on the shorter side, start seeds indoors about 2 to 4 weeks before your last spring frost date. 
  • Be sure to harden off the seedlings before transplanting.
  • Wait until the soil has warmed to about 70ºF (21°C) before sowing seeds. Squash are very sensitive to the cold.

Choosing and Selecting Planting Site

  • Pick a site with full sun and lots of space for sprawling vines. Most full-size winter squash varieties need 50 to 100 square feet to spread. 
  • If your garden space is limited, plant winter squash at the edge of the garden and direct vine growth across the lawn. 
  • You can also grow squash in big 5 to 10 gallon buckets. Or, if you’re even more strapped for space, miniature varieties also exist; they can easily be grown up trellises. 
  • Winter squash are greedy feeders. They prefer very rich soil that is well-drained and not too soggy. 
  • Mix lots of compost or aged manure into the planting site before you sow seeds or transplant seedlings. Learn more about soil amendments and preparing soil.

How to Plant Winter Squash

  • Plant seeds in rows or hills. With hills, the soil will warm more quickly and the seeds will germinate faster. This also helps with drainage.
  • Prepare the soil in advance with lots of aged manure dug deep into the ground (12 to 15 inches). If you don’t have manure, loosen the soil and mix in a 2- to 4-inch layer of compost.
  • Plant the seeds 1 inch deep (4 to 5 seeds per hill). Space hills 4 to 8 feet apart. 
  • In rows, sow seeds 6 to 12 inches apart in rows 6 to 10 feet apart. 
  • The seeds should germinate in about a week with the right soil temperature (70ºF / 21°C or more). 

Thinning Seedlings

  • When seedlings in rows are 2 to 3 inches tall, thin to one plant every 18 to 36 inches by snipping off unwanted plants without disturbing the roots of the remaining ones.
  • When seedlings in hills are 2 to 3 inches tall, thin to 2 to 3 plants per hill by snipping off unwanted plants without disturbing the roots of the remaining ones

See How to Grow Winter Squash

Care

How to Grow Winter Squash

General Care Tips

  • Use row covers to protect plants early in the season and to prevent insect problems. Remember to remove covers before flowering to allow pollination by insects.
  • When weeding around squash plants, do not over-cultivate, or the squash’s shallow roots may be damaged.
  • Squash vines are delicate. Take care not to damage the vines. 
  • Small winter squash varieties can be trained up a trellis.
  • Larger varieties can be trained upward on a trellis, too—though it is a challenge to support the fruit. Netting or slings made of breathable fabric can help to support the heavy fruit.
  • Pruning the vines will help with space, as well as allow the plant’s energy to be concentrated on the remaining vines and fruit.

Watering

  • Winter squash need lots of water. Water one inch per week (about ½ gallon per square foot that the roots cover). Water deeply, especially during fruit set.
  • When watering try to keep leaves and fruit dry. Dampness will cause root rot and other diseases more likely.
  • Add mulch around your winter squash to keep in moisture, suppress weeds, and discourage pests.

Fertilizing

  • Winter squash are heavy feeders. Water regularly with aged manure or compost mixed into the water.
  • Fertilize on a regular basis. Use a high nitrogen formula in early plant growth when plants are about one foot tall, just before vines begin to run. Switch to a fertilizer high in phosphorous just before the blooming period.

Flowering and Fruiting

  • If your first flowers aren’t forming fruits, that’s normal! Squash plants have separate male and female flowers. Male flowers typically appear first. Both male and female blossoms need to be open for pollination. 
  • Pollinators are essential. To attract more bees, try placing a bee house in your garden or plant pollinator flowers nearby.
  • Poor light, too much fertilizer, poor weather at bloom time, and reduced pollinating insect activity can negatively impact fruit set.

Winter squash varieties. Photo by Alina Demidenko/Shutterstock
Some of the many kinds of winter squash. Photo by Alina Demidenko/Shutterstock

 

Pests/Diseases

Harvest/Storage

How to Harvest Winter Squash

Winter squash and pumpkins are generally ready to be harvested in early- to mid-autumn, usually late September through October.

  • Harvest winter squash when they are fully mature for the best success with storage later on. 
  • A winter squash is ripening when its skin turns a deep, solid color (usually orange, tan, or blue).
  • Harvest winter squash when the skin feels hard. Press your nail into the skin; if it resists puncture, it is ripe. The stems will also be tough and the plant’s foliage will start to die back. 
  • Harvest on a dry day after the vines have died back.
  • Leave an inch or two of stem on winter squashes when harvesting them.
  • Cut the squash off the vine carefully with a sharp knife or pruners; do not tear, as you could break the fruit stem or the vines. 
  • Never carry the squash by their stem; if the stem breaks off, this exposes the skin to infection. 

How to Cure Winter Squash

Winter squash must be “cured” before storage. This process helps to dry off excess moisture and to harden the skin, sealing out fungi and bacteria and allowing the squash to keep for longer.

If the weather is dry, just leave your squash on the vine and let them cure outside in the sunshine. If it’s wet or turning colder, bring the squash inside and put them somewhere warm and dry, such as a slatted greenhouse bench or a sunny window. 

How to Store Winter Squash

Store winter squash on racks in a cool (50° to 55°F), dry place. Before you do that, for extra protection, you could give your winter hard-skinned squash a quick wipe with a mild bleach solution (about 1 part household beach to 10 parts water). This serves as a final barrier to fungal and bacterial pathogens. 

Winter squash will last anywhere from a month for spaghetti squash types to 6 months for Hubbard varieties and butternut squash. Many of the hard-rinded Hubbards, butternuts, buttercup, and kabocha types will keep 6 months or more if free from injury, properly cured, and stored in a cool, dry space.

Now imagine all that delectable pumpkin pie and satisfying soup! 

Remember to save some seeds from the heirloom varieties to plant next year. Wash and dry the seeds. Store in an airtight jar in a cool, dark place.

Recommended Varieties

Wit & Wisdom

  • Winter squash have been grown in North America for more than 5,000 years.
  • Winter squash are an excellent source of vitamins A & C, fiber, magnesium, niacin, folate, iron, and potassium. The darker the flesh, the more beta-carotene the squash has to offer. Learn more about winter squash’s health benefits!
  • One cup of cubed winter squash contains about 80 calories, virtually no fat, and very little sodium.
  • Native Americans roasted or boiled winter squash and preserved the flesh as conserves in syrup.
  • Presidents Washington and Jefferson grew squash in their gardens. Give it a try!

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Growing Winter Squash

Botanical Name Cucurbita maxima, C. pepo, C. moschata, C. argyrosperma
Plant Type Vegetable
Sun Exposure Full Sun
Soil Type Loamy
Soil pH Slightly Acidic to Neutral
Bloom Time Summer
Flower Color Orange, Yellow
Hardiness Zones 3, 4, 5, 6, 7, 8, 9
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