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When to Plant Hubbard Squash in Henderson County, IL

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.

Henderson County, Illinois is in USDA Zone 5a. The average last spring frost is April 17 and the first fall frost is October 17, giving you a growing season of approximately 183 days.

At an elevation of 1,278 feet, Henderson County receives approximately 41.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Henderson County, IL (Zone 5a) Moderate season
183 days
Last Spring Frost April 17
183 growing days
First Fall Frost October 17

Henderson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (29 days to spare)
Start indoors: Mar 7 Transplant: Apr 25 🍅 Harvest: Aug 8 – Sep 12
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Aug 14 – Sep 18
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Mar 26 Transplant: May 14 🍅 Harvest: Aug 27 – Oct 1

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 74 gal / 100 sq ft
Hubbard Squash needs ~1,430 GDD — county provides 2,379 GDD Excellent fit

Hubbard Squash Planting Timeline โ€” Henderson County, IL

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 โ€“ Mar 27
Transplant Outdoors May 1 May 1 โ€“ May 15
Direct Sow April 24 Apr 24 โ€“ May 15
Harvest August 14 Aug 14 โ€“ Sep 18

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

100โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

183 days

Growing Tips for Henderson County

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

Frequently Asked Questions

When should I plant Hubbard Squash in Henderson County, IL?

Henderson County is in Zone 5a with an average last frost of April 17. Plan your Hubbard Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Henderson County, IL?

Henderson County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 17 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Henderson County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Henderson County, IL. Local conditions may vary. Last updated: April 2026.