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When to plant Tomatillo in Au Gres, MI

Plant Tomatillo in Au Gres, between May 19 and June 9 — the only viable window. Zone 5b's short season (147 frost-free days) rules out a fall crop.

When to Plant Tomatillo in Au Gres, MI

Arenac County, Michigan Zone 5b July

This month in Arenac County, Michigan

Here's what deserves your attention in Arenac County, Michigan this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost May 12
Avg. first frost October 6
Soil temp (4") 78°F
Watering Moderate
Pest pressure High
Daylight 15 hrs
  1. Time to start tomatillo inside

    You're about 12 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. Harvest tomatillo as they ripen

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

Looking ahead to August
  • First harvests: tomatillo

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

Au Gres, Michigan is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 6, giving you a growing season of approximately 147 days.

At an elevation of 1,015 feet, Arenac County receives approximately 30.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Tomatillo during the growing season.

Au Gres, MI (Zone 5b) Short season
147 days
Last Spring Frost May 12
147 growing days
First Fall Frost October 6

Au Gres Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Tomatillo Planting Risk Windows

Early Start (70% safe) ✓ Fits season (0 days to spare)
Start indoors: Mar 11 Transplant: May 20 🍅 Harvest: Jul 22 – Sep 30
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Mar 17 Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Mar 30 Transplant: Jun 8 🍅 Harvest: Aug 10 – Oct 19

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 Au Gres

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Arenac County is excellent for Tomatillo — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Tomatillo.

Organic Matter

Organic matter is excellent (4.6%) — Tomatillo will thrive.

How to Plant Tomatillo

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

Succession Planting Tomatillo

2
successive plantings in your 147-day season

Sow every 6.9 weeks. Last sowing by Jul 13 to harvest before frost.

Tomatillo Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 731 gal / 100 sq ft

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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.6" 0" ❄️ Dormant
May 4.8" 3.9" 0.9" 💧 Light watering
Jun 4.8" 3.9" 0.9" 💧 Light watering
Jul 4.8" 3.6" 1.2" 💧 Light watering
Aug 4.8" 3.2" 1.6" 💧 Light watering
Sep 4.8" 2.6" 2.2" 💧 Light watering
Oct 4.8" 2.2" 2.6" 🚿 Regular watering
Nov 2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Arenac County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,051 GDD — county provides 2,131 GDD Excellent fit

Tomatillo Planting Timeline — Au Gres, MI

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 19 May 19 – Jun 9
Harvest July 28 Jul 28 – Oct 6

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 Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

147 days in Arenac County

Growing Tips for Tomatillo in Au Gres

Direct sow Tomatillo outdoors after May 12 in Arenac 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 →

When should I plant Tomatillo in Au Gres, MI?

In Au Gres, MI, plant Tomatillo after the last frost (around May 12) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Au Gres, MI for Tomatillo?

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

Can Tomatillo grow in Au Gres's climate?

Yes — Tomatillo grows well in Au Gres's temperate climate. Au Gres averages a 147-day frost-free season, with last frost around May 12 and first frost around October 6.

🌱

Your Arenac County Garden Planner — Free

A 22-page printable planner built for Arenac 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 Arenac County, MI. Local conditions may vary. Last updated: July 2026.