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When to Plant Watermelon in Colfax County, NE

Colfax County, Nebraska Zone 5b May

Top priorities for Colfax County, Nebraska gardeners in May

Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 22
Avg. first frost October 11
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out watermelon

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Fire up the seed-starting tray: watermelon

    Your window is short. These crops want several weeks of indoor growth before they go outside.

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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.

Colfax County, Nebraska is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.

At an elevation of 525 feet, Colfax County receives approximately 25 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Watermelon to ensure they mature before fall.

Colfax County, NE (Zone 5b) Moderate season
172 days
Last Spring Frost April 22
172 growing days
First Fall Frost October 11
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Colfax County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Mar 13 Transplant: May 1 🍅 Harvest: Jul 10 – Aug 28
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Mar 18 Transplant: May 6 🍅 Harvest: Jul 15 – Sep 2
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Apr 3 Transplant: May 22 🍅 Harvest: Jul 31 – Sep 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 Colfax County

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

Soil pH

Your soil pH (6.4–7.7) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Watermelon.

Organic Matter

Organic matter is excellent (4.0%) — Watermelon will thrive.

How to Plant Watermelon

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

Succession Planting Watermelon

2
successive plantings in your 172-day season

Sow every 8 weeks. Last sowing by Jul 03 to harvest before frost.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.6″/week
Watering frequency 2-3 times/week
Season total 2,461 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 6.5" 2.6" 3.9" 🚿 Regular watering
May 6.5" 3.6" 2.9" 💧 Light watering
Jun 6.5" 3.8" 2.7" 💧 Light watering
Jul 6.5" 3.2" 3.3" 🚿 Regular watering
Aug 6.5" 2.8" 3.7" 🚿 Regular watering
Sep 6.5" 2.4" 4.1" 🚿 Regular watering
Oct 6.5" 1.7" 4.8" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Colfax 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 ~1,105 GDD — county provides 2,236 GDD Excellent fit

Watermelon Planting Timeline — Colfax County, NE

Watermelon Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 15 Jul 15 – Sep 2

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Direct Sow
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 · 2-3 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

172 days in Colfax County

Growing Tips for Watermelon in Colfax County

Direct sow Watermelon outdoors after April 22 in Colfax 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 →

Frequently Asked Questions

When should I plant Watermelon in Colfax County, NE?

Colfax County is in Zone 5b with an average last frost of April 22. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colfax County, NE?

Colfax County, Nebraska is in USDA Hardiness Zone 5b. The average last spring frost is April 22 and first fall frost is October 11.

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Your Colfax County Garden Planner — Free

A 24-page printable planner built for Colfax 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 Colfax County, NE. 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.