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When to Plant Hubbard Squash in Foster County, ND

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.

Foster County, North Dakota is in USDA Zone 3b. The average last spring frost is May 10 and the first fall frost is September 30, giving you a growing season of approximately 143 days.

At an elevation of 895 feet, Foster County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Foster County, ND (Zone 3b) Short season
143 days
Last Spring Frost May 10
143 growing days
First Fall Frost September 30

Foster County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 20 Transplant: May 22 🍅 Harvest: Sep 4 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Sep 13 – Oct 4
Safe Start (90%) ✓ Fits season (1 days to spare)
Start indoors: Apr 7 Transplant: Jun 9 🍅 Harvest: Sep 22 – Oct 13

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.

Soil Compatibility in Foster County

How your county's soil matches Hubbard Squash's growing requirements.

Soil pH

Your soil pH (6.5โ€“7.5) overlaps with Hubbard Squash's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Foster County is excellent for Hubbard Squash โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.0%) โ€” Hubbard Squash will thrive.

How to Plant Hubbard Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 285 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Hubbard Squash

Hubbard Squash needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Hubbard Squash Needs Rainfall You Supplement Action
Jan โ€” 0.7" 0" โ„๏ธ Dormant
Feb โ€” 1" 0" โ„๏ธ Dormant
Mar โ€” 1.6" 0" โ„๏ธ Dormant
Apr โ€” 3.1" 0" โ„๏ธ Dormant
May 4.3" 4.6" 0" โœ… Rainfall sufficient
Jun 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Jul 4.3" 3.8" 0.5" ๐Ÿ’ง Light watering
Aug 4.3" 3.1" 1.2" ๐Ÿ’ง Light watering
Sep 4.3" 2.4" 1.9" ๐Ÿ’ง Light watering
Oct โ€” 1.7" 0" โ„๏ธ Dormant
Nov โ€” 0.8" 0" โ„๏ธ Dormant
Dec โ€” 0.8" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Foster County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Hubbard Squash Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" โ€” every day above 50ยฐF deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Hubbard Squash needs ~1,182 GDD — county provides 1,537 GDD Excellent fit

Hubbard Squash Planting Timeline โ€” Foster County, ND

Hubbard Squash Planting Calendar

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

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

100โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 3b

๐Ÿ“† Growing Season

143 days in Foster County

Growing Tips for Hubbard Squash in Foster County

Direct sow Hubbard Squash outdoors after May 10 in Foster County when soil has warmed and frost danger has passed.

Common pests for Hubbard Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hubbard Squash in Foster County, ND?

Foster County is in Zone 3b with an average last frost of May 10. Plan your Hubbard Squash planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Foster County, ND?

Foster County, North Dakota is in USDA Hardiness Zone 3b. The average last spring frost is May 10 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Foster County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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