When to Plant Zucchini in Washington County, MN
Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.
Washington County, Minnesota is in USDA Zone 4a. The average last spring frost is April 23 and the first fall frost is October 9, giving you a growing season of approximately 169 days.
At an elevation of 832 feet, Washington County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Zucchini during the growing season.
Washington County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.9
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 Zucchini's growing requirements.
Soil pH
Your soil pH (5.8–6.9) overlaps with Zucchini's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Washington County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Zucchini will thrive.
How to Plant Zucchini
Succession Planting Zucchini
Sow every 5.1 weeks. Last sowing by Aug 10 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Zucchini
Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.
| Month | Zucchini Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.1" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 5.2" | 3" | 2.2" | 💧 Light watering |
| May | 5.2" | 3.4" | 1.8" | 💧 Light watering |
| Jun | 5.2" | 4.1" | 1.1" | 💧 Light watering |
| Jul | 5.2" | 3.1" | 2.1" | 💧 Light watering |
| Aug | 5.2" | 3.3" | 1.9" | 💧 Light watering |
| Sep | 5.2" | 2.4" | 2.8" | 🚿 Regular watering |
| Oct | 5.2" | 2.4" | 2.8" | 🚿 Regular watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.5" | 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.
Zucchini 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.
Zucchini Planting Timeline — Washington County, MN
Zucchini Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 12 | Mar 12 – Mar 26 |
| Transplant Outdoors | May 14 | May 14 – May 28 |
| Direct Sow | May 7 | May 7 – May 28 |
| Harvest | July 2 | Jul 2 – Aug 27 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 1-2 times/week
📅 Days to Maturity
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 4a
📆 Growing Season
169 days in Washington County
Growing Tips for Zucchini in Washington County
Direct sow Zucchini outdoors after April 23 in Washington County when soil has warmed and frost danger has passed.
Your generous 169.0-day season in Washington County allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.
Common pests for Zucchini 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 after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Zucchini in Other Locations
Frequently Asked Questions
When should I plant Zucchini in Washington County, MN?
Washington County is in Zone 4a with an average last frost of April 23. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.
What planting zone is Washington County, MN?
Washington County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is April 23 and first fall frost is October 9.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Washington County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
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