When to Plant Pumpkin in Washington County, WI
May to-do list for Washington 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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Plant out pumpkin
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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Outdoor sowing time: pumpkin
Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.
June prep starts now
- Starting indoors: pumpkin
Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.
Washington County, Wisconsin is in USDA Zone 5b. The average last spring frost is April 27 and the first fall frost is October 11, giving you a growing season of approximately 167 days.
At an elevation of 1,141 feet, Washington County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Pumpkin during the growing season.
Washington County Soil Profile
Soil Type
Silt Loam
Soil pH
6.1-6.7
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 Washington County
How your county's soil matches Pumpkin's growing requirements.
Soil pH
Your soil pH (6.1–6.7) is within Pumpkin's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Washington County is excellent for Pumpkin — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.3%) — Pumpkin will thrive.
How to Plant Pumpkin
Plant Water Budget
Monthly Watering Guide for Pumpkin
Pumpkin needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.
| Month | Pumpkin Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 5.6" | 3.5" | 2.1" | 💧 Light watering |
| May | 5.6" | 3.5" | 2.1" | 💧 Light watering |
| Jun | 5.6" | 4.2" | 1.4" | 💧 Light watering |
| Jul | 5.6" | 3.3" | 2.3" | 💧 Light watering |
| Aug | 5.6" | 4" | 1.6" | 💧 Light watering |
| Sep | 5.6" | 2.8" | 2.8" | 🚿 Regular watering |
| Oct | 5.6" | 3" | 2.6" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Pumpkin 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.
Pumpkin Planting Timeline — Washington County, WI
Pumpkin 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 | August 10 | Aug 10 – Sep 28 |
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 | — |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.3"/week · 1-2 times/week
📅 Days to Maturity
85–120 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
167 days in Washington County
Growing Tips for Pumpkin in Washington County
Direct sow Pumpkin outdoors after April 27 in Washington County when soil has warmed and frost danger has passed.
Common pests for Pumpkin in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Pumpkin in Other Locations
Frequently Asked Questions
When should I plant Pumpkin in Washington County, WI?
Washington County is in Zone 5b with an average last frost of April 27. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, WI?
Washington County, Wisconsin is in USDA Hardiness Zone 5b. The average last spring frost is April 27 and first fall frost is October 11.
Your Washington County Garden Planner — Free
A 24-page printable planner built for Washington 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.