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When to plant Arugula in Washington County, IA

Plant Arugula in Washington County from April 7 to April 28 in spring. Washington County sits in USDA Zone 5b, with last frost around April 21 and first frost on October 14. A second sowing from August 5 to August 19 extends the harvest into fall.

When to Plant Arugula in Washington County, IA

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.

Washington County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 14, giving you a growing season of approximately 176 days.

At an elevation of 542 feet, Washington County receives approximately 30.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Arugula to ensure they mature before fall.

Washington County, IA (Zone 5b) Moderate season
176 days
Last Spring Frost April 21
176 growing days
First Fall Frost October 14

Washington County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Arugula Planting Timeline — Washington County, IA

Arugula Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 7 Apr 7 – Apr 28
Harvest May 26 May 26 – Jul 28
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

30–50 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

176 days in Washington County

Growing Tips for Washington County

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 Washington County, IA?

Washington County is in Zone 5b with an average last frost of April 21. Plan your Arugula planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, IA?

Washington County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 14.

When should I plant Arugula in Washington County, IA?

In Washington County, IA, plant Arugula after the last frost (around April 21) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Washington County, IA for Arugula?

Washington 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 Washington County's climate?

Yes — Arugula grows well in Washington County's temperate climate. Washington County averages a 176-day frost-free season, with last frost around April 21 and first frost around October 14.

🌱

Your Washington County Garden Planner — Free

A 22-page printable planner built for Washington 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 Washington County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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