When to Plant Zucchini in Pennington 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.
Pennington County, Minnesota is in USDA Zone 3b. The average last spring frost is May 10 and the first fall frost is September 30, giving you a growing season of approximately 143 days.
At an elevation of 854 feet, Pennington County receives approximately 35.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Zucchini to ensure they mature before fall.
Pennington County Soil Profile
Soil Type
Silt Loam
Soil pH
5.9-7.1
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 Pennington County
How your county's soil matches Zucchini's growing requirements.
Soil pH
Your soil pH (5.9–7.1) overlaps with Zucchini's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Pennington County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.9%) — Zucchini will thrive.
How to Plant Zucchini
Succession Planting Zucchini
Sow every 5.1 weeks. Last sowing by Aug 01 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 | — | 1.3" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | — | 3.3" | 0" | ❄️ Dormant |
| May | 5.2" | 4.3" | 0.9" | 💧 Light watering |
| Jun | 5.2" | 4.4" | 0.8" | 💧 Light watering |
| Jul | 5.2" | 3.9" | 1.3" | 💧 Light watering |
| Aug | 5.2" | 3" | 2.2" | 💧 Light watering |
| Sep | 5.2" | 3.3" | 1.9" | 💧 Light watering |
| Oct | — | 2.9" | 0" | ❄️ Dormant |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Pennington 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 — Pennington County, MN
Zucchini Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 29 | Mar 29 – Apr 12 |
| Transplant Outdoors | May 31 | May 31 – Jun 14 |
| Direct Sow | May 24 | May 24 – Jun 14 |
| Harvest | July 19 | Jul 19 – Sep 13 |
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 | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · Only during dry spells
📅 Days to Maturity
45–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 3b
📆 Growing Season
143 days in Pennington County
Growing Tips for Zucchini in Pennington County
Direct sow Zucchini outdoors after May 10 in Pennington County when soil has warmed and frost danger has passed.
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 Pennington County, MN?
Pennington County is in Zone 3b with an average last frost of May 10. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.
What planting zone is Pennington County, MN?
Pennington County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 10 and first fall frost is September 30.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Pennington County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.
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