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When to Plant Arugula in Cornucopia, WI

Bayfield County, Wisconsin Zone 4b July

Bayfield County, Wisconsin gardeners: here's your July plan

July is a pivotal month for Bayfield County, Wisconsin gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 14
Avg. first frost October 3
Soil temp (4") 70°F
Watering Low
Pest pressure Moderate
Daylight 15.3 hrs
  1. Harvest arugula as they ripen

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

  2. Get arugula in for a late-season harvest

    Fall crops get sweeter with a light frost. Don't be afraid of cool nights.

To set up a strong August, finish these tasks
  • First harvests: arugula

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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.

Cornucopia, Wisconsin is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is October 3, giving you a growing season of approximately 142 days.

At an elevation of 619 feet, Bayfield County receives approximately 36.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Arugula to ensure they mature before fall.

Cornucopia, WI (Zone 4b) Short season
142 days
Last Spring Frost May 14
142 growing days
First Fall Frost October 3

Cornucopia Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.8

Drainage

Well Drained

Arugula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Start indoors: Mar 26 Transplant: May 7 🍅 Harvest: Jun 11 – Aug 13
Recommended (50%) ✓ Fits season (44 days to spare)
Start indoors: Apr 2 Transplant: May 14 🍅 Harvest: Jun 18 – Aug 20
Safe Start (90%) ✓ Fits season (44 days to spare)
Start indoors: Apr 20 Transplant: Jun 1 🍅 Harvest: Jul 6 – Sep 7

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 Cornucopia

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

Soil pH

Your soil pH (5.8–6.8) overlaps with Arugula's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Bayfield 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

5
successive plantings in your 142-day season

Sow every 3.4 weeks. Last sowing by Aug 14 to harvest before frost.

For a dedicated fall crop, sow by Jul 11.

Arugula Water Budget

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

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

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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 2.6" 4.4" 0" ✅ Rainfall sufficient
Jun 2.6" 4.7" 0" ✅ Rainfall sufficient
Jul 2.6" 4.4" 0" ✅ Rainfall sufficient
Aug 2.6" 3.4" 0" ✅ Rainfall sufficient
Sep 2.6" 3.2" 0" ✅ Rainfall sufficient
Oct 2.6" 3.1" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Bayfield 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 ~400 GDD — county provides 1,420 GDD Excellent fit

Arugula Planting Timeline — Cornucopia, WI

Arugula Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 7 May 7 – May 28
Harvest June 18 Jun 18 – Aug 20
Fall Sowing July 11 Jul 11 – Jul 25

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

142 days in Bayfield County

Growing Tips for Arugula in Cornucopia

Direct sow Arugula outdoors after May 14 in Bayfield County when soil has warmed and frost danger has passed.

Your generous 142.0-day season in Bayfield 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 →

🌱

Your Bayfield County Garden Planner — Free

A 22-page printable planner built for Bayfield 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 Bayfield County, WI. Local conditions may vary. Last updated: July 2026.