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When to Plant Hubbard Squash in USDA Zone 3b

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 3b, the average last spring frost is around May 10 and the first fall frost is around September 22, giving you a growing season of approximately 135 days.

Zone 3b Short season
135 days
Last Spring Frost May 10
135 growing days
First Fall Frost September 22

Hubbard Squash Planting Timeline — Zone 3b

Where Is USDA Zone 3b?

The map below highlights the states that contain Zone 3b. 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 3b

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 24 May 24 – Jun 14
Harvest September 13 Sep 13 – Oct 4

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 3b Planting Calendar PDF

Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 3b with start dates, transplant windows, and harvest times.

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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

-35°F to -30°F average annual minimum

Growing Season

135 days (Zone 3b average)

Planting Specifications

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

Growing Tips for Zone 3b

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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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 3b?

In Zone 3b, plan your Hubbard Squash planting around the average last frost date of May 10. Start seeds indoors around March 29. Direct sow outdoors around May 24. Transplant seedlings around May 31.

Can Hubbard Squash grow in Zone 3b?

Yes, Hubbard Squash can grow well in Zone 3b, hardy in USDA zones 3a through 10b. Zone 3b has a growing season of approximately 135 days, which is sufficient for Hubbard Squash (100-120 days to maturity).

When can I harvest Hubbard Squash in Zone 3b?

In Zone 3b, expect to harvest Hubbard Squash from September 13 – October 4. Hubbard Squash takes 100-120 days from planting to harvest.

What is the last frost date for Zone 3b?

The average last spring frost in Zone 3b is around May 10, and the first fall frost is around September 22. This gives a growing season of approximately 135 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 3b, 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.