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Winter Squash: How to Plant, Grow, Harvest, and Cure Winter Squash | The Old Farmer's Almanac

Winter Squash

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DLeonis/Getty Images
Botanical Name
Cucurbita maxima, C. pepo, C. moschata, C. argyrosperma
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How to Plant, Grow, Harvest, and Cure Winter Squash

The Editors
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Growing winter squash requires some patience, but this garden vegetable is well worth the wait—and most varieties have a long shelf life after harvest. From butternut squash to acorn squash, learn how to plant, grow, harvest, and cure winter squash in your home garden!

About Winter Squash

Because winter squash requires a long growing season (generally from 75 to 100 frost-free days), the seeds are generally planted by late May in northern locations to early July in extremely southern states. See your local frost dates and length of growing season.

Winter squash are harvested in late summer or autumn, just before or after their fruits reach full maturity. Squash have a relatively long shelf life. Some varieties will keep through winter, hence the name winter squash. Varieties include acorn, butternut, delicata, Hubbard, pumpkin, and spaghetti.

Despite the great diversity of squash, most commonly grown cultivated varieties belong to one of three species:

  1. Cucurbita pepo
  2. C. moschata
  3. C. maxima

Over several generations, these plants have been cultivated to produce fruit in all kinds of shapes, colors, and flavors.

The Three Sisters

Squash is one of the three plants grown in the traditional Native American style called the Three Sisters, along with beans and corn. When grown together, the squash serves as a ground cover to prevent weeds from growing, beans provide natural fertilizer for all three plants, and corn provides a support system for the beans. Learn more about the Three Sisters.

Planting

Plant squash in a location with full sun and lots of space for sprawling vines. Most full-size winter squash varieties need 50 to 100 square feet to spread. Soil must be well fed and moist (not soggy) and well draining. Mix aged manure and/or compost (about 50% native soil to organic matter) deep into the soil a couple weeks before planting.

How to Plant Squash

  • Direct-sow (i.e., plant seeds directly in the ground) when all danger of frost has passed and the soil is at least 60°F, preferably 70°F.  Squash are very sensitive to the cold.
  • If you have a short growing season, start seeds in peat pots 2 to 4 weeks before your last spring frost date. Squash seedlings do not always transplant well, so handle the roots gently.

How to Plant Squash

  • If you plan to grow only a few plants, use 2 to 3 tablespoons of a balanced (10-10-10) fertilizer for each hill. Scatter the fertilizer evenly over a 2-foot by 2-foot area. Work it into the top 3 to 4 inches of soil. Or, for a larger garden area, add 2 to 3 pounds of balanced fertilizer for each 100 square feet.
  • Sow seeds in level ground 1 inch deep with seeds 2 to 3 feet apart. Or, sow 3 to 4 seeds close together in small mounds (or hills; the soil is warmer off the ground) in rows 3 to 6 feet apart.
  • Consider planting a few squash seeds in midsummer to avoid problems from squash vine borers and other early-season pests and diseases.
  • The seeds should germinate in about a week with the right soil temperature (70ºF / 21°C or more). 
  • If necessary, use row covers or frame protection in cold climates for the first few weeks of spring. 
  • Use row covers to prevent insect problems early in the season Remember to remove covers before flowering to allow pollination by insects.

See this helpful video on how to sow seeds.

Growing
  • Mulch to discourage weeds, retain moisture, and protect shallow roots.
  • Water thoroughly, frequently, and consistently, with at least 1 inch per week. Water at soil level and try to keep leaves and fruit dry. Dampness will make root rot and other diseases more likely.
  • When weeding around squash plants, do not over-cultivate, or the squash’s shallow roots may be damaged.

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

Fertilizing

  • When the first blooms appear, scratch about 2 tablespoons of all-purpose fertilizer around each hill. Or, if growing squash in rows, side-dress. This give plants a boost as they try to produce fruit or blooms. Do not let the fertilizer touch the plants. Water the plants after fertilizing.
  • Once vegetables or flowers start growing and producing buds, you can scratch a small amount of all-purpose organic fertilizer into the soil around the base of the plant and water in.

Pruning the vines will help with space, as well as allow the plant’s energy to be concentrated on the remaining vines and fruit.

Flowering and Fruiting

  • Poor pollination can result in squash flowers that do not bear fruit or that bear small fruit. Pollinator activity is reduced by any chemicals, poor weather at bloom time, and lack of habitat. To attract more bees, try placing a bee house in your garden or plant pollinator flowers nearby.
  • If your first flowers aren’t forming fruits, that’s normal! Squash plants have separate male and female flowers. Males appear first on long thin stalks. Female flowers follow with an immature fruit at the bottom. To fruit, pollen from male flowers must be transferred to the female flower by bees. Or, the gardener can help manually with a cotton swab or paint brush. See our article on how to hand pollinate your squash blossoms for better yields.
Harvesting

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

  • Unlike summer squash, which is harvested when tender and a bit immature, harvest winter squash when it is fully mature. The vine leaves die back and turn brown, the stems dry out and get tough, and the rind is deep in color and hard. If you can pierce the skin with your fingernail, it is not mature. 
  • 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. 

Once you harvest, don’t forget to clean up the old squash vines to avoid disease! Add vines to the compost pile if you have one. They’ll break down and you can work the compost into the soil before the next planting season.

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, which allows the squash to be kept 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

Before storing winter squash, dip it into or wash with a low-concentration bleach rinse (1/2 cup bleach to 5 cups water) to sanitize the skin and eliminate bacteria. Air-dry the fruit.

Store in a cool (40° to 50°F), dry, dark place with good circulation. Many varieties of squash will last most of the winter. Note: Acorn will not keep for more than a few weeks. Occasionally rotate and look for signs of rot. Remove any squash that shows signs of decay.

Try to save some seeds if you grow heirloom varieties (not hybrids) to plant next year. Wash and dry the seeds. Store in an airtight jar in a cool, dark place.

Wit and Wisdom
  • The word “squash” derives from askutasquash, the Narragansett Native American word meaning “eaten raw or uncooked.”
  • Winter squash have been grown in North America for more than 5,000 years.
  • Presidents Washington and Jefferson grew squash in their gardens. Give it a try!
  • So-called squash bees—Peponapis and Xenoglassa—are excellent Cucurbita pollinators and especially so for butternut squash (and summer squash). Look for them among the flowers in the first few hours after sunrise.
Pests/Diseases

Squash bugs are generally considered the most troublesome pest. They need to be managed early. There are several organic approaches to control:

  • Handpick and scrape off those egg clusters early and as best you can
  • Spray neem on egg clusters and juvenile squash bugs
  • Grow young plants under row covers (uncover when flowering begins)
  • Delay squash planting until early summer as the natural predators of squash bugs become more numerous and active as summer progresses.

→ See our Squash Bug pest page for more information.

Squash Pests and Diseases

Pest/Disease Type Symptoms Control/Prevention
Aphids Insect Misshapen/yellow leaves; distorted flowers/fruit; sticky “honeydew” (excrement); sooty, black mold Grow companion plants; knock off with water spray; apply insecticidal soap; put banana or orange peels around plants; wipe leaves with a 1 to 2 percent solution of dish soap (no additives) and water every 2 to 3 days for 2 weeks; add native plants to invite beneficial insects
Blossom-end rot Disorder Dark, water-soaked spots on blossom end of fruit (opposite stem) may enlarge and become sunken and leathery Remove affected fruit; plant at proper soil temperature; water deeply and evenly; use mulch; maintain proper soil pH (around 6.5) and nutrient levels; avoid excessive nitrogen; provide good drainage; prevent root damage
Cucumber beetles Insect Holes in leaves/flowers; rasped fruit; plants stunted/die; can spread bacterial wilt (Bacterial wilt signs: wilting; plants die; ends of cut stems, when pressed together for 10 seconds and pulled apart, release stringy, white sap) Handpick; mulch heavily; use row covers; destroy plants infected with bacterial wilt
Cucumber mosaic virus Virus Varies with plant, but may include stunting, mottled green/yellow/white pattern or ringed spots on leaves/fruit; distorted leaf growth; warts on fruit Destroy infected plants; choose resistant varieties and certified virus-free seed; use row covers; disinfect tools; weed; control aphids; use mulch
Downy mildew Fungus Yellow, angular spots on upper leaf surfaces that turn brown; white/purple/gray cottony growth on leaf undersides only; distorted leaves; defoliation Remove plant debris; choose resistant varieties; ensure good air circulation; avoid overhead watering
Powdery mildew Fungus Typically, white spots on upper leaf surfaces expand to flour-like coating over entire leaves; foliage may yellow/die; distortion/stunting of leaves/flowers Destroy infected leaves or plants; choose resistant varieties; plant in full sun, if possible; ensure good air circulation; spray plants with 1 teaspoon baking soda dissolved in 1 quart water; destroy crop residue
Squash bugs Insect Many small, yellow/brown/black spots on leaves; wilt; scarred fruit Handpick; crush yellow/bronze egg clusters on leaf undersides; lay boards on soil and check for pests underneath each morning; remove plant debris; use row covers; rotate crops
Squash vine borers Insect Vines wilt suddenly; plants die; mushy area and/or green to orange-yellow, sawdust-like excrement on/near base of plant stem If detected early, slit infested stem lengthwise halfway to remove borer(s), then bury the cut in moist soil to encourage rooting; wrap seedling stems in aluminum foil collar; catch moths with yellow sticky traps; use row covers if no pests previously, but uncover before flowering; destroy crop residue; rotate crops
Stinkbugs Insect Yellow/white blotches on leaves; scarred, dimpled, or distorted fruit; shriveled seeds; eggs, often keg-shape, in clusters on leaf undersides Destroy crop residue; handpick (bugs emit odor, wear gloves); destroy eggs; spray nymphs with insecticidal soap; use row covers; weed; till soil in fall
Cooking Notes
  • Winter squash is often baked in casseroles or on its own. Cook all types of squash only until tender to keep the nutritional content.
  • Mmmm, Pumpkin Pie! See our collection of Best Pumpkin Recipes!
  • Winter squash is a good source of vitamin A and has fair amounts of vitamin C. 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.

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