When to Plant Hubbard Squash in Isabella County, MI
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.
Isabella County, Michigan is in USDA Zone 5a. The average last spring frost is May 4 and the first fall frost is October 13, giving you a growing season of approximately 162 days.
At an elevation of 1,136 feet, Isabella County receives approximately 35.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.
Isabella County Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.8
Drainage
Well Drained
Plant Planting Risk Windows
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
Hubbard Squash Planting Timeline — Isabella County, MI
Hubbard Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 30 | Mar 30 – Apr 13 |
| Transplant Outdoors | May 18 | May 18 – Jun 1 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Harvest | August 31 | Aug 31 – Oct 5 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Moderate — regular watering
Days to Maturity
100–120 days
Soil pH
6 – 7
USDA Zone
Zone 5a
Growing Season
162 days
Growing Tips for Isabella 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
Level Up Your Garden
Hubbard Squash in Other Locations
Frequently Asked Questions
When should I plant Hubbard Squash in Isabella County, MI?
Isabella County is in Zone 5a with an average last frost of May 4. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Isabella County, MI?
Isabella County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 4 and first fall frost is October 13.
Plan Your Garden with Confidence
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