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Squash Seed Starting Tips

Squash seedling

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Squash are tender warm-weather crops. Sow squash seeds directly in the garden one week or more after the last frost in spring. For an earlier start, sow squash seeds indoors 2 to 4 weeks before the last frost and transplant seedlings to the garden 2 to 4 weeks after the last frost.

The optimal planting soil temperature for squash is 60 to 85°F (16-29°C). The optimal growing air temperature for squash is 60 to 75°F (16-24°C).

In reverse-season climates, mild winter climates, a second squash crop can be planted in early autumn for harvest in winter.

Good Products for Growing Squash at Amazon:

Squash sprout, seedling growing in a pot indoors

Planting squash

Squashes are easy to grow but they generally take up a lot of garden space. A vining squash plant needs about 10 square feet of growing room if allowed to sprawl. Squash can be trained vertically on a trellis or tripod to save room. Most squashes are available in bush varieties which take less room.

Squash grows best in humus-rich, well-drained, sandy loam. Add aged compost or a commercial organic planting mix to a depth of 12 inches. Squashes are often planted atop mounds or hills allowing the vines to run down the hill where they can be trained to circle the mound.

Squash are heavy feeders needing a moderate amount of nitrogen and a high amount of phosphorus. Add a slow-release organic fertilizer to the soil at planting time. Plant squash in full sun.

Zucchini seedlings
Zucchini seedlings

Squash planting details

  • Sowing depth: 1-2 inches (2.5-5cm)
  • Space between plants after thinning: 2-3 feet for summer squash; 3-4 feet between winter squash
  • Days to sprout: 7-12
  • Days to harvest: 50-60 for summer squash; 80-120 for winter squash
  • Storage period: 1-2 weeks for summer squash; 8-24 weeks for winter squash
  • Seeds per 100-row feet: 1-2 ounces
  • Yield per 100-row feet: 200 pounds
  • Suggested summer varieties: Aristocrat, Gold Rush, Scallopini, Early Straightneck
  • Suggested winter varieties; Waltham Butternut, Blue Hubbard, Turk’s Turban, Royal Acorn, Vegetable Spaghetti
Winter squash plants seed start
Squash plants early in the growing season

Squash sowing and planting tips

  • Grow squash from seeds or seedlings.
  • Squash seeds are viable for 6 years.
  • Direct sow squash in the garden in spring after all danger of frost has passed and the soil has warmed to 70°F (21°C). In warm-winter regions, sow squash in midwinter for harvest in early summer.
  • Squash seeds will not germinate at a soil temperature below 66°F (18°C).
  • To start plants indoors, sow seeds in peat pots 4 to 3 weeks before the last frost in spring. The indoor temperature should be 66°F to 85°F (18-29°C) until germination.
  • Sow seed ½ to 1 inch (1.3-2.5 cm) deep.
  • Seeds germinate in 4 to 10 days at 85°F (29°C) or warmer.
  • Transplant squash into the garden after the soil has warmed to at least 70°F (21°C).
  • Space plants in the garden 12 to 18 inches (30-45 cm) apart in all directions.
  • Squash will benefit from the warm soil created by planting on hills or mounds; raise the soil 12 inches (30 cm) tall and 20 inches (50 cm) wide and grow individual plants on hills. Space hills 4 to 5 feet (1.2-1.5 m) apart.
  • Water to keep the soil from drying.
  • Fertilize with fish emulsion or a soluble complete fertilizer at half strength.
  • Add aged compost to planting beds in advance of transplanting.
  • Squash prefers a soil pH range of 5.5 to 6.8.
  • Grow squash in full sun for the best yield.
  • Avoid planting winter squash where cucumbers or melons have grown recently.
  • Common squash pest enemies include aphids, cucumber beetles, flea beetles, squash bugs, squash vine borers, slugs, and snails.
  • Common diseases include bacterial wilt, fusarium wilt, downy mildew, powdery mildew, and cucumber mosaic.

Interplanting: Plant winter squash with bush beans, corn, dill, eggplant, lettuce, cucumbers, summer squash, and tomatoes.

Container Growing: Squashes are not a good choice for container growing. They require significant room to spread and grow.

Squash planting calendar

  • 3-4 weeks before the last frost in spring: start seed indoors for transplanting into the garden later.
  • 2-3 weeks after the last frost in spring: transplant seedlings to the garden.
  • 3 weeks after the last frost in spring: direct sow seed in the garden; minimum soil temperature 65°

Squash planting dates

(These dates are for the Northern Hemisphere)

Average date of the last frostPlanting dates
Jan. 30Feb. 1-Apr.15
Feb. 8Feb. 15-Apr. 15
Feb. 18Mar. 1-Apr. 15
Feb. 28Mar. 15-Apr. 30
Mar. 10Apr. 1-May 15
Mar. 20Apr. 10-May
Mar. 30Apr. 10-June 1
Apr. 10Apr. 20-June 1
Apr. 20May 1-June 15
Apr. 30May 1-Jun. 10
May 10May 10-June 15
May 20May 20-June 15
May 30June 1-20
June 10June 10-20
Young zucchini in the garden
Young squash in the garden

Squash harvest time

Summer squashes such as crookneck, scallop, straight-neck, and zucchini mature in 50 to 65 days. Winter squashes such as acorn, banana, buttercup, delicata, Hubbard, spaghetti, and Turk’s turban mature in 60 to 110 days.

Summer squash should be harvested while young and tender when the skin yields to thumb pressure. Winter squash which takes longer to mature should not be harvested until as late as possible in autumn but before the first hard frost. The shells should be hard enough to resist denting by a thumbnail.

Squash on mound seed starting
Winter squash will benefit from the warm soil created by planting on hills or mounds;

There are many types and varieties of winter squash; here are a few:

  • Acorn: acorn-shaped, dark green fruit to 2 pounds.
  • Banana: smooth gray-green skin, light orange flesh to 18 inches long.
  • Butternut: tan-yellow skin, orange fleshy pulp; elongated pear-shape with a bulbous compartment of seeds at the blossom end
  • Buttercup: squat acorn shape; blackish-green rind with yellow-orange flesh.
  • Cushaw: green-striped gourd to 15 inches long.
  • Hubbard: bluish, gray, orange, or dark green, smooth and warty skin.
  • Pumpkins are winter squashes.
  • Turban: bright-colored, turban-shaped shells 6 to 7 inches in diameter.

Summer squash recommended varieties

There are many types and varieties of summer squash; here are a few:

  • Zucchini: glossy, dark green or yellow cylindrical fruits; ‘Gold Rush’, ‘Spacemaster’; ‘Eightball’ is round.
  • Scallop or pattypan: ‘Sunburst’, ‘Starship’, ‘Golden Scallopini Bush’.
  • Round or globe: ‘Eight Ball’.
  • Crookneck and Straightneck

Botanical Names: Cucurbita maxima, Cucurbita moschata, Cucurbita pepo.

Squash are members of the Cucurbitaceae family; other members are cucumbers, melons, watermelons, and pumpkins.

Squash articles at Harvest to Table:

How to Grow Summer and Winter Squash

How to Plant and Grow Pumpkins

Squash Seed Starting Tips

Pumpkin Seed Starting Tips

How to Harvest and Store Summer Squash

How to Harvest, Cure, and Store Winter Squash

How to Harvest and Store Pumpkins

Eight Ways to Cook and Serve Summer Squash

Seven Ways to Cook and Serve Winter Squash

Five Ways to Cook Pumpkins

How to Make Pumpkin Ice Cream

How to Make Creamy Pumpkin Soup

Pumpkin With Coconut Curry

Piloncillo and Pumpkin

How to Cook and Serve Squash Blossoms

Squash Growing Problems: Troubleshooting

Squash Vine Borer Organic Pest Control

Squash Bug Organic Pest Control

Corn, Beans, and Squash: The Three Sisters

Garden Planning Books at Amazon:

Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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