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When to Plant Hubbard Squash in Gladwin County, MI

Gladwin County, Michigan Zone 6a May

May in Gladwin County, Michigan — your action list

May is a pivotal month for Gladwin County, Michigan gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 9
Avg. first frost October 6
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Plant out hubbard squash

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Outdoor sowing time: hubbard squash

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Get ahead of June
  • Starting indoors: hubbard squash

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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.

Gladwin County, Michigan is in USDA Zone 6a. The average last spring frost is May 9 and the first fall frost is October 6, giving you a growing season of approximately 150 days.

At an elevation of 832 feet, Gladwin County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Gladwin County, MI (Zone 6a) Moderate season
150 days
Last Spring Frost May 9
150 growing days
First Fall Frost October 6
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Gladwin County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Mar 26 Transplant: May 14 🍅 Harvest: Aug 27 – Oct 1
Recommended (50%) ✗ May not fit
Start indoors: Apr 4 Transplant: May 23 🍅 Harvest: Sep 5 – Oct 10
Safe Start (90%) ✓ Fits season (1 days to spare)
Start indoors: Apr 15 Transplant: Jun 3 🍅 Harvest: Sep 16 – Oct 21

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 Gladwin County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Hubbard Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Gladwin County is excellent for Hubbard Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.9%) — 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
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.9" 0" ❄️ Dormant
May 4.3" 4.4" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 3.8" 0.5" 💧 Light watering
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Gladwin County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,348 GDD — county provides 1,837 GDD Excellent fit

Hubbard Squash Planting Timeline — Gladwin County, MI

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 16 May 16 – Jun 6
Harvest September 5 Sep 5 – Oct 10

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

150 days in Gladwin County

Growing Tips for Hubbard Squash in Gladwin County

Direct sow Hubbard Squash outdoors after May 09 in Gladwin 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 Gladwin County, MI?

Gladwin County is in Zone 6a with an average last frost of May 9. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Gladwin County, MI?

Gladwin County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 9 and first fall frost is October 6.

🌱

Your Gladwin County Garden Planner — Free

A 24-page printable planner built for Gladwin County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 Gladwin County, MI. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.