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When to Plant Tomatoes in Manitowoc County, WI

Tomatoes are the most popular home garden crop, available in thousands of varieties from tiny cherries to massive beefsteaks. They are warm-season plants needing full sun.

Manitowoc County, Wisconsin is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 661 feet, Manitowoc County receives approximately 39.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Tomatoes during the growing season.

Manitowoc County, WI (Zone 5a) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12

Manitowoc County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Feb 28 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 5 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 24
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Mar 23 Transplant: Jun 1 🍅 Harvest: Aug 3 – Oct 12

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 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

Tomatoes needs ~1,106 GDD — county provides 2,516 GDD Excellent fit

Tomatoes Planting Timeline โ€” Manitowoc County, WI

Tomatoes 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 0.5" deep ยท 24" apart ยท Rows 36" 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

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

165 days

Growing Tips for Manitowoc County

Start seeds indoors 6-8 weeks before last frost. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Level Up Your Garden

๐ŸŒพ Save Your Own Tomatoes Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Scoop seeds from ripe fruit; ferment 2-3 days to remove gel coating.
Storage Store airtight; viable 4-6 years at 35ยฐF, under 45% humidity.

Isolate 25 ft between varieties for purity. Use open-pollinated varieties for true-to-type seeds.

Frequently Asked Questions

When should I plant Tomatoes in Manitowoc County, WI?

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

What planting zone is Manitowoc County, WI?

Manitowoc County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Manitowoc County gardeners in Zone 5a 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 Manitowoc County, WI. Local conditions may vary. Last updated: April 2026.