When to Plant Watermelon in Green Lake County, WI
This month in Green Lake County, Wisconsin
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Time to transplant watermelon
Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.
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Direct-sow watermelon
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
June prep starts now
- Starting indoors: watermelon
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.
Green Lake County, Wisconsin is in USDA Zone 5a. The average last spring frost is April 27 and the first fall frost is October 14, giving you a growing season of approximately 170 days.
At an elevation of 592 feet, Green Lake County receives approximately 32.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Watermelon to ensure they mature before fall.
Green Lake County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.1
Drainage
Well Drained
Plant Planting Risk Windows
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 Green Lake County
How your county's soil matches Watermelon's growing requirements.
Soil pH
Your soil pH (6.2–7.1) is within Watermelon's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Green Lake County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.2%) — Watermelon will thrive.
How to Plant Watermelon
Succession Planting Watermelon
Sow every 8 weeks. Last sowing by Jul 06 to harvest before frost.
Plant Water Budget
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 6.5" | 3.1" | 3.4" | 🚿 Regular watering |
| May | 6.5" | 3.5" | 3" | 💧 Light watering |
| Jun | 6.5" | 3.8" | 2.7" | 💧 Light watering |
| Jul | 6.5" | 4" | 2.5" | 💧 Light watering |
| Aug | 6.5" | 3.3" | 3.2" | 💧 Light watering |
| Sep | 6.5" | 3.1" | 3.4" | 🚿 Regular watering |
| Oct | 6.5" | 2.4" | 4.1" | 🚿 Regular watering |
| Nov | — | 2.1" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Green Lake 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 Planting Timeline — Green Lake County, WI
Watermelon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 23 | Mar 23 – Apr 6 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | May 4 | May 4 – May 25 |
| Harvest | July 20 | Jul 20 – Sep 7 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
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: ideal
🗺️ USDA Zone
Zone 5a
📆 Growing Season
170 days in Green Lake County
Growing Tips for Watermelon in Green Lake County
Direct sow Watermelon outdoors after April 27 in Green Lake 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
Check more plant combinations with our Companion Planting Checker →
Watermelon in Other Locations
Frequently Asked Questions
When should I plant Watermelon in Green Lake County, WI?
Green Lake County is in Zone 5a with an average last frost of April 27. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Green Lake County, WI?
Green Lake County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is April 27 and first fall frost is October 14.
Your Green Lake County Garden Planner — Free
A 24-page printable planner built for Green Lake County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.