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When to Plant Pumpkin in Kennebec County, ME

Kennebec County, Maine Zone 5b May

Your May gardening checklist

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 10
Avg. first frost October 5
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.6 hrs
  1. Get pumpkin in the ground

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

  2. Scatter pumpkin into prepared beds

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

Before June arrives, get these ready
  • Starting indoors: pumpkin

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Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.

Kennebec County, Maine is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 1,032 feet, Kennebec County receives approximately 42.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Pumpkin to ensure they mature before fall.

Kennebec County, ME (Zone 5b) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Kennebec County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 30 Transplant: May 18 🍅 Harvest: Aug 17 – Oct 5
Recommended (50%) ✗ May not fit
Start indoors: Apr 5 Transplant: May 24 🍅 Harvest: Aug 23 – Oct 11
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jun 10 🍅 Harvest: Sep 9 – Oct 28

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 Kennebec County

How your county's soil matches Pumpkin's growing requirements.

Soil pH

Your soil pH (5.1–6.4) is more acidic than Pumpkin prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). Annual compost additions will help Pumpkin.

How to Plant Pumpkin

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

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.2″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 124 gal / 100 sq ft

Monthly Watering Guide for Pumpkin

Pumpkin needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Pumpkin Needs Rainfall You Supplement Action
Jan 3.3" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 5.6" 3.7" 1.9" 💧 Light watering
Jun 5.6" 3.7" 1.9" 💧 Light watering
Jul 5.6" 3.9" 1.7" 💧 Light watering
Aug 5.6" 4" 1.6" 💧 Light watering
Sep 5.6" 3.9" 1.7" 💧 Light watering
Oct 5.6" 3.8" 1.8" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Kennebec County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Pumpkin 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.

Pumpkin needs ~1,332 GDD — county provides 1,924 GDD Excellent fit

Pumpkin Planting Timeline — Kennebec County, ME

Pumpkin 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 August 23 Aug 23 – 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 Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Only during dry spells

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Kennebec County

Growing Tips for Pumpkin in Kennebec County

Direct sow Pumpkin outdoors after May 10 in Kennebec County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pumpkin in Kennebec County, ME?

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

What planting zone is Kennebec County, ME?

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

🌱

Your Kennebec County Garden Planner — Free

A 24-page printable planner built for Kennebec County (Zone 5b). 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 Kennebec County, ME. 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.