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When to plant Tomatillo in Mills County, IA

Spring Tomatillo in Mills County goes in May 3–May 24, once nighttime temps stop dipping near freezing.

When to Plant Tomatillo in Mills County, IA

Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.

Mills County, Iowa is in USDA Zone 5b. The average last spring frost is April 26 and the first fall frost is October 7, giving you a growing season of approximately 164 days.

At an elevation of 1,355 feet, Mills County receives approximately 35.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Tomatillo during the growing season.

Mills County, IA (Zone 5b) Moderate season
164 days
Last Spring Frost April 26
164 growing days
First Fall Frost October 7

Mills County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Tomatillo Planting Timeline — Mills County, IA

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors May 10 May 10 – May 24
Direct Sow May 3 May 3 – May 24
Harvest July 12 Jul 12 – Sep 20

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

164 days in Mills County

Growing Tips for Mills County

Start seeds indoors 6-8 weeks before last frost. Plant at least two plants for cross-pollination. Harvest when fruits fill the husk and it begins to split.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Dill

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tomatillo in Mills County, IA?

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

What planting zone is Mills County, IA?

Mills County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 26 and first fall frost is October 7.

When should I plant Tomatillo in Mills County, IA?

In Mills County, IA, plant Tomatillo after the last frost (around April 26) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Mills County, IA for Tomatillo?

Mills County sits in USDA Zone 5b. Tomatillo grows reliably in zones 4a through 11b, so it's a good fit here.

Can Tomatillo grow in Mills County's climate?

Yes — Tomatillo grows well in Mills County's temperate climate. Mills County averages a 164-day frost-free season, with last frost around April 26 and first frost around October 7.

🌱

Your Mills County Garden Planner — Free

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

Sources & credits

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