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When to plant Tomatoes in Clarke County, IA

Plant Tomatoes in Clarke County, when soil hits 50°F — usually May 1. Continue planting through May 22 for the spring crop.

When to Plant Tomatoes in Clarke County, IA

Tomatoes

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.

Clarke County, Iowa is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 11, giving you a growing season of approximately 170 days.

At an elevation of 1,182 feet, Clarke County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Tomatoes during the growing season.

Clarke County, IA (Zone 5b) Moderate season
170 days
Last Spring Frost April 24
170 growing days
First Fall Frost October 11

Clarke County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

How Much Tomatoes to Grow

10-15 lbs
Average yield per plant
3
Plants per person
6 sq ft
Space per person

For a family of 4, plant approximately 12 tomatoes plants in about 24 sq ft. In Clarke County's 170-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Tomatoes Planting Timeline — Clarke County, IA

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors February 27 Feb 27 – Mar 13
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 1 May 1 – May 22
Harvest July 10 Jul 10 – Sep 18

Plant 0.5" deep · 24" apart · Rows 36" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 5b

📆 Growing Season

170 days in Clarke County

Growing Tips for Clarke 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

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, 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 Clarke County, IA?

Clarke County is in Zone 5b with an average last frost of April 24. Plan your Tomatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clarke County, IA?

Clarke County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 11.

When should I plant Tomatoes in Clarke County, IA?

In Clarke County, IA, plant Tomatoes after the last frost (around April 24) and before the first frost (around October 11). Best results when soil holds above 50°F.

What growing zone is Clarke County, IA for Tomatoes?

Clarke County sits in USDA Zone 5b. Tomatoes grows reliably in zones 3a through 11b, so it's a good fit here.

Can Tomatoes grow in Clarke County's climate?

Yes — Tomatoes grows well in Clarke County's temperate climate. Clarke County averages a 170-day frost-free season, with last frost around April 24 and first frost around October 11.

🌱

Your Clarke County Garden Planner — Free

A 22-page printable planner built for Clarke 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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