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When to Plant Tomatillo in Delta County, MI

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

Delta County, Michigan is in USDA Zone 4b. The average last spring frost is May 12 and the first fall frost is October 14, giving you a growing season of approximately 155 days.

At an elevation of 921 feet, Delta County receives approximately 41.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Tomatillo to ensure they mature before fall.

Delta County, MI (Zone 4b) Moderate season
155 days
Last Spring Frost May 12
155 growing days
First Fall Frost October 14

Delta County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 4 Transplant: May 27 🍅 Harvest: Jul 29 – Oct 7
Recommended (50%) ✓ Fits season (1 days to spare)
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 4 – Oct 13
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Aug 18 – Oct 27

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
1.1″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Tomatillo needs ~888 GDD — county provides 1,898 GDD Excellent fit

Tomatillo Planting Timeline โ€” Delta County, MI

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors June 2 Jun 2 โ€“ Jun 16
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest August 4 Aug 4 โ€“ Oct 13

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April โ€”
May Direct Sow
June Transplant Outdoors Direct Sow
July โ€”
August Harvest
September Harvest
October Harvest
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 4b

Growing Season

155 days

Growing Tips for Delta 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 Delta County, MI?

Delta County is in Zone 4b with an average last frost of May 12. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Delta County, MI?

Delta County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 12 and first fall frost is October 14.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Delta County gardeners in Zone 4b 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 Delta County, MI. Local conditions may vary. Last updated: April 2026.