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When to Plant Winter Melon in Merrimack County, NH

Merrimack County, New Hampshire Zone 5b April

Top priorities for Merrimack County, New Hampshire gardeners in April

We've pulled the most time-sensitive tasks for Merrimack County, New Hampshire this April and put them front and centre. Tackle them in order.

Avg. last frost May 7
Avg. first frost October 10
Soil temp (4") 44°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
Coming up in May — start thinking about
  • Transplants going out: winter melon
  • Direct-sowing: winter melon

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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.

Merrimack County, New Hampshire is in USDA Zone 5b. The average last spring frost is May 7 and the first fall frost is October 10, giving you a growing season of approximately 156 days.

At an elevation of 836 feet, Merrimack County receives approximately 40.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Winter Melon during the growing season.

Merrimack County, NH (Zone 5b) Moderate season
156 days
Last Spring Frost May 7
156 growing days
First Fall Frost October 10

Merrimack County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 6 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 2
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 12 Transplant: May 21 🍅 Harvest: Aug 20 – Oct 8
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Mar 22 Transplant: May 31 🍅 Harvest: Aug 30 – Oct 18

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 Merrimack County

How your county's soil matches Winter Melon's growing requirements.

Soil pH

Your soil pH (4.9–6.7) is more acidic than Winter Melon prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). 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 2.9" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Merrimack 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 ~1,522 GDD — county provides 2,262 GDD Excellent fit

Winter Melon Planting Timeline — Merrimack County, NH

Winter Melon Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 – Mar 26
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 14 May 14 – Jun 4
Harvest August 20 Aug 20 – Oct 8

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

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

156 days in Merrimack County

Growing Tips for Winter Melon in Merrimack County

Direct sow Winter Melon outdoors after May 07 in Merrimack 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 Merrimack County, NH?

Merrimack County is in Zone 5b with an average last frost of May 7. Plan your Winter Melon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Merrimack County, NH?

Merrimack County, New Hampshire is in USDA Hardiness Zone 5b. The average last spring frost is May 7 and first fall frost is October 10.

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Your Merrimack County Garden Planner — Free

A 24-page printable planner built for Merrimack 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 Merrimack County, NH. Local conditions may vary. Last updated: April 2026.

Sources & credits

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