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When to Plant Arugula in Walsh County, ND

Walsh County, North Dakota Zone 4a May

Top priorities for Walsh County, North Dakota gardeners in May

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

Avg. last frost May 14
Avg. first frost September 30
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Transplant arugula outside

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Direct-sow arugula

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

Before June arrives, get these ready
  • Starting indoors: arugula
  • 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.

Walsh County, North Dakota is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 30, giving you a growing season of approximately 139 days.

At an elevation of 553 feet, Walsh County receives approximately 32.7 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Arugula to ensure they mature before fall.

Walsh County, ND (Zone 4a) Short season
139 days
Last Spring Frost May 14
139 growing days
First Fall Frost September 30
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Walsh County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Mar 28 Transplant: May 9 🍅 Harvest: Jun 13 – Aug 15
Recommended (50%) ✓ Fits season (41 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 13 Transplant: May 25 🍅 Harvest: Jun 29 – Aug 31

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 Walsh County

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

Soil pH

Your soil pH (6.2–7.5) overlaps with Arugula's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Arugula.

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 139-day season

Sow every 3.4 weeks. Last sowing by Aug 11 to harvest before frost.

For a dedicated fall crop, sow by Jul 08.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.0″/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 0.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 2.6" 5.2" 0" ✅ Rainfall sufficient
Jun 2.6" 5.3" 0" ✅ Rainfall sufficient
Jul 2.6" 3.6" 0" ✅ Rainfall sufficient
Aug 2.6" 4.2" 0" ✅ Rainfall sufficient
Sep 2.6" 3.2" 0" ✅ Rainfall sufficient
Oct 1.9" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Walsh 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 ~430 GDD — county provides 1,494 GDD Excellent fit

Arugula Planting Timeline — Walsh County, ND

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 8 Jul 8 – Jul 22

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
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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 4a

📆 Growing Season

139 days in Walsh County

Growing Tips for Arugula in Walsh County

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

Your generous 139.0-day season in Walsh 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 Walsh County, ND?

Walsh County is in Zone 4a with an average last frost of May 14. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Walsh County, ND?

Walsh County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 30.

🌱

Your Walsh County Garden Planner — Free

A 24-page printable planner built for Walsh 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 Walsh County, ND. 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.