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When to Plant Hubbard Squash in USDA Zone 4a

Hubbard squash is a large, bumpy-skinned winter squash with dense, sweet, dry flesh ideal for baking and pies. The hard shell allows storage for 6 months or more.

In Zone 4a, the average last spring frost is around May 6 and the first fall frost is around September 28, giving you a growing season of approximately 145 days.

Zone 4a Short season
145 days
Last Spring Frost May 6
145 growing days
First Fall Frost September 28

Hubbard Squash Planting Timeline — Zone 4a

Where Is USDA Zone 4a?

The map below highlights the states that contain Zone 4a. Click any state to see the Hubbard Squash planting schedule for that location.

Prints a clean, ink-friendly version without maps or navigation.

Hubbard Squash Planting Calendar — Zone 4a

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors May 27 May 27 – Jun 10
Direct Sow May 20 May 20 – Jun 10
Harvest September 9 Sep 9 – Oct 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August
September Harvest
October Harvest
November
December

Free Zone 4a Planting Calendar PDF

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Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate — regular watering

Days to Maturity

100–120 days

Soil pH

6 – 7

Zone Temperature Range

-30°F to -25°F average annual minimum

Growing Season

145 days (Zone 4a average)

Planting Specifications

Planting Depth1 inches
Plant Spacing30 inches apart
Row Spacing42 inches between rows

Growing Tips for Zone 4a

Start seeds indoors in short-season areas. Requires ample space and rich soil. Harvest when the skin is very hard and the color is deep. Cure in the sun before storing.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Level Up Your Garden

Saving Hubbard Squash Seeds

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LED Grow Lights $25-60

Full-spectrum LED lights for starting seeds indoors when daylight is limited.

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Seedling Heat Mat $15-35

Warm soil for faster germination of heat-loving crops like tomatoes and peppers.

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Floating Row Covers $12-30

Protect plants from frost, wind, and pests while letting light and water through.

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Frequently Asked Questions

When should I plant Hubbard Squash in Zone 4a?

In Zone 4a, plan your Hubbard Squash planting around the average last frost date of May 6. Start seeds indoors around March 25. Direct sow outdoors around May 20. Transplant seedlings around May 27.

Can Hubbard Squash grow in Zone 4a?

Yes, Hubbard Squash can grow well in Zone 4a, hardy in USDA zones 3a through 10b. Zone 4a has a growing season of approximately 145 days, which is sufficient for Hubbard Squash (100-120 days to maturity).

When can I harvest Hubbard Squash in Zone 4a?

In Zone 4a, expect to harvest Hubbard Squash from September 9 – October 14. Hubbard Squash takes 100-120 days from planting to harvest.

What is the last frost date for Zone 4a?

The average last spring frost in Zone 4a is around May 6, and the first fall frost is around September 28. This gives a growing season of approximately 145 days. These are 50% probability dates — actual frost dates vary year to year.

What should I plant next to Hubbard Squash?

Good companion plants for Hubbard Squash include Corn, Green Beans. These companions can help with pest control, pollination, and nutrient sharing.

🌱

Plan Your Garden with Confidence

Get our free Garden Planner — organize your planting dates for Zone 4a, track your crops, and plan your garden season from seed to harvest.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals, University Cooperative Extension planting guides. Planting dates are estimates based on average frost dates — local conditions may vary. Last updated: April 2026.