When to Plant Watermelon in Forest County, WI
May to-do list for Forest County, Wisconsin
Each item below is timed to Forest County, Wisconsin's frost dates and soil temperatures. Skip nothing, stress about nothing.
A few tasks this May that'll pay off in June
- Transplants going out: watermelon
- Direct-sowing: 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.
Forest County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 30, giving you a growing season of approximately 133 days.
At an elevation of 556 feet, Forest County receives approximately 34.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Watermelon to ensure they mature before fall.
Forest County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.7
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 Forest County
How your county's soil matches Watermelon's growing requirements.
Soil pH
Your soil pH (5.8–6.7) overlaps with Watermelon's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Forest County is excellent for Watermelon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Watermelon will thrive.
How to Plant Watermelon
Succession Planting Watermelon
Sow every 8 weeks. Last sowing by Jun 22 to harvest before frost.
Plant Water Budget
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | — | 3.1" | 0" | ❄️ Dormant |
| May | 6.5" | 4" | 2.5" | 💧 Light watering |
| Jun | 6.5" | 4.1" | 2.4" | 💧 Light watering |
| Jul | 6.5" | 3.6" | 2.9" | 💧 Light watering |
| Aug | 6.5" | 4.1" | 2.4" | 💧 Light watering |
| Sep | 6.5" | 3.4" | 3.1" | 💧 Light watering |
| Oct | — | 2.5" | 0" | ❄️ Dormant |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Forest 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 — Forest County, WI
Watermelon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 8 | Apr 8 – Apr 22 |
| Transplant Outdoors | June 10 | Jun 10 – Jun 24 |
| Direct Sow | June 3 | Jun 3 – Jun 24 |
| Harvest | August 19 | Aug 19 – Oct 7 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | — |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
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: acceptable
🗺️ USDA Zone
Zone 4b
📆 Growing Season
133 days in Forest County
Growing Tips for Watermelon in Forest County
Direct sow Watermelon outdoors after May 20 in Forest 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.
Recommended Watermelon Varieties for Forest County
Compact, early melons for shorter seasons
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 Forest County, WI?
Forest County is in Zone 4b with an average last frost of May 20. Plan your Watermelon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Forest County, WI?
Forest County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 30.
Your Forest County Garden Planner — Free
A 24-page printable planner built for Forest County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.