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When to Plant Tomatillo in Clinton 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.

Clinton County, Michigan is in USDA Zone 5b. The average last spring frost is April 30 and the first fall frost is October 13, giving you a growing season of approximately 166 days.

At an elevation of 519 feet, Clinton County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Tomatillo to ensure they mature before fall.

Clinton County, MI (Zone 5b) Moderate season
166 days
Last Spring Frost April 30
166 growing days
First Fall Frost October 13

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 2 Transplant: May 11 🍅 Harvest: Jul 13 – Sep 21
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Mar 5 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 24
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Mar 25 Transplant: Jun 3 🍅 Harvest: Aug 5 – Oct 14

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 Clinton County

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

Soil pH

Your soil pH (5.9โ€“6.7) overlaps with Tomatillo's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

The silt loam soil in Clinton County is excellent for Tomatillo โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Tomatillo.

Organic Matter

Organic matter is excellent (4.8%) โ€” Tomatillo will thrive.

How to Plant Tomatillo

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Tomatillo

3
successive plantings in your 166-day season

Sow every 6.9 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,006 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Tomatillo

Tomatillo needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Tomatillo Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.4" 0" โ„๏ธ Dormant
Apr 4.8" 2.9" 1.9" ๐Ÿ’ง Light watering
May 4.8" 3.8" 1" ๐Ÿ’ง Light watering
Jun 4.8" 4.1" 0.7" ๐Ÿ’ง Light watering
Jul 4.8" 3.7" 1.1" ๐Ÿ’ง Light watering
Aug 4.8" 3.9" 0.9" ๐Ÿ’ง Light watering
Sep 4.8" 3" 1.8" ๐Ÿ’ง Light watering
Oct 4.8" 2.7" 2.1" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clinton County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Tomatillo 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" โ€” every day above 50ยฐF 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.

Tomatillo needs ~942 GDD — county provides 2,158 GDD Excellent fit

Tomatillo Planting Timeline โ€” Clinton County, MI

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 5 Mar 5 โ€“ Mar 19
Transplant Outdoors May 14 May 14 โ€“ May 28
Direct Sow May 7 May 7 โ€“ May 28
Harvest July 16 Jul 16 โ€“ Sep 24

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 Transplant Outdoors Direct Sow
June โ€”
July Harvest
August Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 5b

๐Ÿ“† Growing Season

166 days in Clinton County

Growing Tips for Tomatillo in Clinton County

Direct sow Tomatillo outdoors after April 30 in Clinton County when soil has warmed and frost danger has passed.

Common pests for Tomatillo in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

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 Clinton County, MI?

Clinton County is in Zone 5b with an average last frost of April 30. Plan your Tomatillo planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clinton County, MI?

Clinton County, Michigan is in USDA Hardiness Zone 5b. The average last spring frost is April 30 and first fall frost is October 13.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clinton County, MI. Local conditions may vary. Last updated: April 2026.