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When to Plant Winter Melon in Sullivan County, NH

Sullivan County, New Hampshire Zone 5b May

May in Sullivan County, New Hampshire — your action list

A quick May briefing for Sullivan County, New Hampshire gardeners — what's urgent, what's next, and what can wait.

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. Move winter melon into the garden

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Put winter melon seeds straight in the ground

    Your soil is 59°F — warm enough for these to germinate without babying.

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Winter melon (wax gourd) is a large Asian squash with a waxy white coating that allows long storage. The mild flesh is used in soups and stir-fries.

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 Winter Melon 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
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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: Mar 11 Transplant: May 20 🍅 Harvest: Aug 19 – Oct 7
Recommended (50%) ✗ May not fit
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Aug 25 – Oct 13
Safe Start (90%) ✗ May not fit
Start indoors: Mar 30 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 Winter Melon's growing requirements.

Soil pH

Your soil pH (5.0–6.6) is more acidic than Winter Melon prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Winter Melon.

How to Plant Winter Melon

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 Winter Melon

Winter Melon needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Winter Melon 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 4.3" 3.6" 0.7" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.3" 1" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 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.

Winter Melon 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.

Winter Melon needs ~1,365 GDD — county provides 1,924 GDD Excellent fit

Winter Melon Planting Timeline — Sullivan County, NH

Winter Melon Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
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 Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Harvest
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

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Sullivan County

Growing Tips for Winter Melon in Sullivan County

Direct sow Winter Melon outdoors after May 12 in Sullivan County when soil has warmed and frost danger has passed.

Common pests for Winter Melon 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 3-4 weeks early. Provide ample space for sprawling vines. Harvest when the waxy coating develops on the rind. Fruits can weigh 15-30 pounds.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Winter Melon in Sullivan County, NH?

Sullivan County is in Zone 5b with an average last frost of May 12. Plan your Winter Melon 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.

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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.