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When to Plant Zucchini in Otter Tail County, MN

Otter Tail County, Minnesota Zone 4a May

Your May game plan for Otter Tail County, Minnesota

We've pulled the most time-sensitive tasks for Otter Tail County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost May 11
Avg. first frost September 28
Soil temp (4") 49°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Sow zucchini where they'll grow

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

To set up a strong June, finish these tasks
  • Transplants going out: zucchini
  • Starting indoors: zucchini

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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.

Otter Tail County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 28, giving you a growing season of approximately 140 days.

At an elevation of 571 feet, Otter Tail County receives approximately 40.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Zucchini to ensure they mature before fall.

Otter Tail County, MN (Zone 4a) Short season
140 days
Last Spring Frost May 11
140 growing days
First Fall Frost September 28
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Otter Tail County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 17 Transplant: May 19 🍅 Harvest: Jul 7 – Sep 1
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Mar 30 Transplant: Jun 1 🍅 Harvest: Jul 20 – Sep 14
Safe Start (90%) ✓ Fits season (20 days to spare)
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Jul 30 – Sep 24

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 Otter Tail County

How your county's soil matches Zucchini's growing requirements.

Soil pH

Your soil pH (6.3–6.8) is within Zucchini's preferred range (6.0–7.5).

Soil Texture

The silt loam soil in Otter Tail County is excellent for Zucchini — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is excellent (5.2%) — Zucchini will thrive.

How to Plant Zucchini

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Zucchini

3
successive plantings in your 140-day season

Sow every 5.1 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.2″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 525 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.9" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 5.2" 4.2" 1" 💧 Light watering
Jun 5.2" 5.7" 0" ✅ Rainfall sufficient
Jul 5.2" 5" 0.2" 💧 Light watering
Aug 5.2" 4.3" 0.9" 💧 Light watering
Sep 5.2" 3.1" 2.1" 💧 Light watering
Oct 3.4" 0" ❄️ Dormant
Nov 2.8" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Otter Tail 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 needs ~525 GDD — county provides 1,400 GDD Excellent fit

Zucchini Planting Timeline — Otter Tail County, MN

Zucchini Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors June 1 Jun 1 – Jun 15
Direct Sow May 25 May 25 – Jun 15
Harvest July 20 Jul 20 – Sep 14

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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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: ideal

🗺️ USDA Zone

Zone 4a

📆 Growing Season

140 days in Otter Tail County

Growing Tips for Zucchini in Otter Tail County

Direct sow Zucchini outdoors after May 11 in Otter Tail 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.

Recommended Zucchini Varieties for Otter Tail County

Quick-producing varieties for shorter seasons

Black Beauty (50d) Raven (48d) Eight Ball (40d)

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Otter Tail County, MN?

Otter Tail County is in Zone 4a with an average last frost of May 11. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Otter Tail County, MN?

Otter Tail County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 28.

🌱

Your Otter Tail County Garden Planner — Free

A 24-page printable planner built for Otter Tail County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Otter Tail County, MN. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.