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When to plant Watermelon in Pullman,

Watermelon planted in Pullman between May 9 and May 30 matures in 100 days — well before the October 14 first frost.

When to Plant Watermelon in Pullman, MI

Watermelon
Pullman, MI Zone 6a June

June in Pullman, MI — your action list

June is a pivotal month for Pullman, MI gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 2
Avg. first frost October 14
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Time to start watermelon inside

    Label every cell. You will absolutely forget which is which otherwise.

Looking ahead to July
  • First harvests: watermelon

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Watermelon is a sprawling vine crop that produces sweet, juicy fruits in hot weather. Varieties range from personal-sized icebox types to 50-pound giants.

Pullman, Michigan is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 14, giving you a growing season of approximately 165 days.

At an elevation of 1,257 feet, Allegan County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Watermelon during the growing season.

Pullman, MI (Zone 6a) Moderate season
165 days
Last Spring Frost May 2
165 growing days
First Fall Frost October 14
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Pullman Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Watermelon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Mar 23 Transplant: May 11 🍅 Harvest: Jul 20 – Sep 7
Recommended (50%) ✓ Fits season (32 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12
Safe Start (90%) ✓ Fits season (25 days to spare)
Start indoors: Apr 16 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 1

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 Pullman

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

Soil pH

Your soil pH (6.2–6.7) is within Watermelon's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Watermelon will thrive.

How to Plant Watermelon

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

Succession Planting Watermelon

2
successive plantings in your 165-day season

Sow every 8 weeks. Last sowing by Jul 06 to harvest before frost.

Watermelon Water Budget

Plant needs
1.5″/week
Rainfall provides
1.0″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 801 gal / 100 sq ft

Monthly Watering Guide for Watermelon

Watermelon needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Watermelon Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 6.5" 3.5" 3" 💧 Light watering
Jun 6.5" 4.9" 1.6" 💧 Light watering
Jul 6.5" 4.2" 2.3" 💧 Light watering
Aug 6.5" 3.4" 3.1" 💧 Light watering
Sep 6.5" 3.6" 2.9" 💧 Light watering
Oct 6.5" 3.1" 3.4" 🚿 Regular watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Watermelon 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.

Watermelon needs ~1,232 GDD — county provides 2,392 GDD Excellent fit

Watermelon Planting Timeline — Pullman, MI

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 – Apr 11
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 9 May 9 – May 30
Harvest July 25 Jul 25 – Sep 12

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

165 days in Allegan County

Growing Tips for Watermelon in Pullman

Direct sow Watermelon outdoors after May 02 in Allegan County when soil has warmed and frost danger has passed.

Common pests for Watermelon 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 or direct sow after soil is warm. Plant on mounds with plenty of space. Check ripeness by looking for a yellow ground spot and dull thump when tapped.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

When should I plant Watermelon in Pullman, ?

In Pullman, , plant Watermelon after the last frost (around May 2) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Pullman, for Watermelon?

Pullman sits in USDA Zone 6a. Watermelon grows reliably in zones 4a through 11b, so it's a good fit here.

Can Watermelon grow in Pullman's climate?

Yes — Watermelon grows well in Pullman's temperate climate. Pullman averages a 165-day frost-free season, with last frost around May 2 and first frost around October 14.

🌱

Your Allegan County Garden Planner — Free

A 22-page printable planner built for Allegan County (Zone 6a). 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 Allegan County, MI. Local conditions may vary. Last updated: June 2026.