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When to Plant Arugula in Cottonwood County, MN

Cottonwood County, Minnesota Zone 4b April

April in Cottonwood County, Minnesota — your action list

Here's what deserves your attention in Cottonwood County, Minnesota this month. Everything below is tailored to Zone 4b and timed around your local frost dates.

Avg. last frost April 29
Avg. first frost October 8
Soil temp (4") 42°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
  1. Move arugula into the garden

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

  2. Plant arugula from seed, right in the garden

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

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Arugula is a fast-growing cool-season green with a peppery, nutty flavor. It is excellent in salads and can be harvested as baby greens or mature leaves.

Cottonwood County, Minnesota is in USDA Zone 4b. The average last spring frost is April 29 and the first fall frost is October 8, giving you a growing season of approximately 162 days.

At an elevation of 1,066 feet, Cottonwood County receives approximately 32.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82°F, so choose short-season varieties of Arugula to ensure they mature before fall.

Cottonwood County, MN (Zone 4b) Moderate season
162 days
Last Spring Frost April 29
162 growing days
First Fall Frost October 8

Cottonwood County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🍅 Harvest: May 27 – Jul 29
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Mar 18 Transplant: Apr 29 🍅 Harvest: Jun 3 – Aug 5
Safe Start (90%) ✓ Fits season (65 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jun 18 – Aug 20

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 Cottonwood County

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

Soil pH

Your soil pH (6.0–7.0) is within Arugula's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Arugula will thrive.

How to Plant Arugula

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Arugula

6
successive plantings in your 162-day season

Sow every 3.4 weeks. Last sowing by Aug 19 to harvest before frost.

For a dedicated fall crop, sow by Jul 16.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Arugula

Arugula needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Arugula Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.6" 3.5" 0" ✅ Rainfall sufficient
May 2.6" 4" 0" ✅ Rainfall sufficient
Jun 2.6" 3.6" 0" ✅ Rainfall sufficient
Jul 2.6" 4.1" 0" ✅ Rainfall sufficient
Aug 2.6" 3.1" 0" ✅ Rainfall sufficient
Sep 2.6" 3.1" 0" ✅ Rainfall sufficient
Oct 2.6" 2.2" 0.4" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Cottonwood County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Arugula 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.

Arugula needs ~460 GDD — county provides 1,863 GDD Excellent fit

Arugula Planting Timeline — Cottonwood County, MN

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 22 Apr 22 – May 13
Harvest June 3 Jun 3 – Aug 5
Fall Sowing July 16 Jul 16 – Jul 30

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

162 days in Cottonwood County

Growing Tips for Arugula in Cottonwood County

Direct sow Arugula outdoors after April 29 in Cottonwood County when soil has warmed and frost danger has passed.

Your generous 162.0-day season in Cottonwood County allows multiple plantings of Arugula. Sow every 15.0 days for continuous harvest.

Common pests for Arugula in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2-3 weeks for continuous harvest. Provide afternoon shade in warm weather to prevent bolting. Harvest outer leaves first to extend production.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Arugula in Cottonwood County, MN?

Cottonwood County is in Zone 4b with an average last frost of April 29. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cottonwood County, MN?

Cottonwood County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 29 and first fall frost is October 8.

🌱

Your Cottonwood County Garden Planner — Free

A 24-page printable planner built for Cottonwood 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.

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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 Cottonwood County, MN. Local conditions may vary. Last updated: April 2026.

Sources & credits

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