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When to Plant Tomatillo in Lucas 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.

Lucas County, Iowa is in USDA Zone 5a. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 638 feet, Lucas County receives approximately 41.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Tomatillo during the growing season.

Lucas County, IA (Zone 5a) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Lucas County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (27 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🍅 Harvest: Jul 1 – Sep 9
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Feb 24 Transplant: May 5 🍅 Harvest: Jul 7 – Sep 15
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Mar 9 Transplant: May 18 🍅 Harvest: Jul 20 – Sep 28

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Only during dry spells
Season total 2 gal / 100 sq ft
Tomatillo needs ~1,106 GDD — county provides 2,668 GDD Excellent fit

Tomatillo Planting Timeline โ€” Lucas County, IA

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 โ€“ Mar 10
Transplant Outdoors May 5 May 5 โ€“ May 19
Direct Sow April 28 Apr 28 โ€“ May 19
Harvest July 7 Jul 7 โ€“ Sep 15

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“85 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

175 days

Growing Tips for Lucas 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Tomatillo in Lucas County, IA?

Lucas County is in Zone 5a with an average last frost of April 21. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Lucas County, IA?

Lucas County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 21 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Lucas County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Lucas County, IA. Local conditions may vary. Last updated: April 2026.