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When to plant Arugula in Monroe County County,

Monroe County County sits in USDA Zone 5b. Plant Arugula between April 12 (after last frost on April 26) and May 3. A second sowing from August 4 to August 18 extends the harvest into fall.

When to Plant Arugula in Monroe County, IA

Monroe County, Iowa Zone 5b June

What to do in June

Welcome to June in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 26
Avg. first frost October 13
Soil temp (4") 71°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start harvesting arugula

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

A few tasks this June that'll pay off in July
  • 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.

Monroe County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 968 feet, Monroe County receives approximately 32.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Arugula during the growing season.

Monroe County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13

Monroe County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Arugula Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: May 23 – Jul 25
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: May 31 – Aug 2
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 17 – Aug 19

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 Monroe County

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

Soil pH

Your soil pH (6.2–7.3) overlaps with Arugula's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Monroe 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 10 weeks before your first frost date for a fall harvest.

Succession Planting Arugula

6
successive plantings in your 170-day season

Sow every 3.4 weeks. Last sowing by Aug 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Arugula Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/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 1.5" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.6" 2.8" 0" ✅ Rainfall sufficient
May 2.6" 3.5" 0" ✅ Rainfall sufficient
Jun 2.6" 4.3" 0" ✅ Rainfall sufficient
Jul 2.6" 4" 0" ✅ Rainfall sufficient
Aug 2.6" 3.3" 0" ✅ Rainfall sufficient
Sep 2.6" 3" 0" ✅ Rainfall sufficient
Oct 2.6" 2.3" 0.3" 💧 Light watering
Nov 2.1" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Monroe 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 ~610 GDD — county provides 2,592 GDD Excellent fit

Arugula Planting Timeline — Monroe County, IA

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 12 Apr 12 – May 3
Harvest May 31 May 31 – Aug 2
Fall Sowing August 4 Aug 4 – Aug 18

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 Harvest
June Harvest
July Harvest
August Fall Sowing 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 5b

📆 Growing Season

170 days in Monroe County

Growing Tips for Arugula in Monroe County

Direct sow Arugula outdoors after April 26 in Monroe County when soil has warmed and frost danger has passed.

Your generous 170.0-day season in Monroe 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 Monroe County, IA?

Monroe County is in Zone 5b with an average last frost of April 26. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Monroe County, IA?

Monroe County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 13.

When should I plant Arugula in Monroe County, ?

In Monroe County, , plant Arugula after the last frost (around April 26) and before the first frost (around October 13). Best results when soil holds above 50°F.

What growing zone is Monroe County, for Arugula?

Monroe County sits in USDA Zone 5b. Arugula grows reliably in zones 3a through 11b, so it's a good fit here.

Can Arugula grow in Monroe County's climate?

Yes — Arugula grows well in Monroe County's temperate climate. Monroe County averages a 170-day frost-free season, with last frost around April 26 and first frost around October 13.

🌱

Your Monroe County Garden Planner — Free

A 22-page printable planner built for Monroe County (Zone 5b). 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 Monroe County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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