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When to Plant Pumpkin in Sullivan County, NH

Sullivan County, New Hampshire Zone 5b May

May to-do list for Sullivan County, New Hampshire

Your garden in Sullivan County, New Hampshire is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 12
Avg. first frost October 7
Soil temp (4") 59°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Time to transplant pumpkin

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Outdoor sowing time: pumpkin

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Get ahead of June
  • 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.

Sullivan County, New Hampshire is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 7, giving you a growing season of approximately 148 days.

At an elevation of 495 feet, Sullivan County receives approximately 39.5 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.

Sullivan County, NH (Zone 5b) Short season
148 days
Last Spring Frost May 12
148 growing days
First Fall Frost October 7

Sullivan County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 7
Recommended (50%) ✗ May not fit
Start indoors: Apr 7 Transplant: May 26 🍅 Harvest: Aug 25 – Oct 13
Safe Start (90%) ✗ May not fit
Start indoors: Apr 20 Transplant: Jun 8 🍅 Harvest: Sep 7 – 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 Sullivan County

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

Soil pH

Your soil pH (5.0–6.6) is more acidic than Pumpkin prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). 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
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 236 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 2.7" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.6" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 5.6" 3.6" 2" 💧 Light watering
Jun 5.6" 3.3" 2.3" 💧 Light watering
Jul 5.6" 4.3" 1.3" 💧 Light watering
Aug 5.6" 3.3" 2.3" 💧 Light watering
Sep 5.6" 3.2" 2.4" 💧 Light watering
Oct 5.6" 3.1" 2.5" 💧 Light watering
Nov 3" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Sullivan 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 — Sullivan County, NH

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors April 7 Apr 7 – Apr 21
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 19 May 19 – Jun 9
Harvest August 25 Aug 25 – Oct 13

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 Sullivan County

Growing Tips for Pumpkin in Sullivan County

Direct sow Pumpkin outdoors after May 12 in Sullivan 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 Sullivan County, NH?

Sullivan County is in Zone 5b with an average last frost of May 12. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sullivan County, NH?

Sullivan County, New Hampshire is in USDA Hardiness Zone 5b. The average last spring frost is May 12 and first fall frost is October 7.

🌱

Your Sullivan County Garden Planner — Free

A 24-page printable planner built for Sullivan 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 Sullivan County, NH. 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.