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When to Plant Hubbard Squash in Penobscot County, ME

Penobscot County, Maine Zone 5a May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Penobscot County, Maine.

Avg. last frost May 10
Avg. first frost October 2
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant hubbard squash

    Your last frost (May 10) has passed. These warm-season crops can handle outdoor soil now.

  2. Outdoor sowing time: hubbard squash

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

A few tasks this May that'll pay off in 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.

Penobscot County, Maine is in USDA Zone 5a. The average last spring frost is May 10 and the first fall frost is October 2, giving you a growing season of approximately 145 days.

At an elevation of 842 feet, Penobscot County receives approximately 38.8 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.

Penobscot County, ME (Zone 5a) Short season
145 days
Last Spring Frost May 10
145 growing days
First Fall Frost October 2

Penobscot County Soil Profile

Soil Type

Silt Loam

Soil pH

4.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: May 21 🍅 Harvest: Sep 3 – Oct 8
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Sep 6 – Oct 11
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 8 🍅 Harvest: Sep 21 – Oct 26

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 Penobscot County

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

Soil pH

Your soil pH (4.8–6.7) is more acidic than Hubbard Squash prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Hubbard Squash.

How to Plant Hubbard Squash

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

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 2.4" 0" ❄️ Dormant
Feb 2.3" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 3.2" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Penobscot 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 1,776 GDD Excellent fit

Hubbard Squash Planting Timeline — Penobscot County, ME

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors April 5 Apr 5 – Apr 19
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest September 6 Sep 6 – Oct 11

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

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: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

145 days in Penobscot County

Growing Tips for Hubbard Squash in Penobscot County

Direct sow Hubbard Squash outdoors after May 10 in Penobscot 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 Penobscot County, ME?

Penobscot County is in Zone 5a with an average last frost of May 10. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Penobscot County, ME?

Penobscot County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 10 and first fall frost is October 2.

🌱

Your Penobscot County Garden Planner — Free

A 24-page printable planner built for Penobscot County (Zone 5a). 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 Penobscot County, ME. Local conditions may vary. Last updated: May 2026.

Sources & credits

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