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When to Plant Tomatoes in Ransom County, ND

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.

Ransom County, North Dakota is in USDA Zone 4a. The average last spring frost is May 8 and the first fall frost is October 3, giving you a growing season of approximately 148 days.

At an elevation of 517 feet, Ransom County receives approximately 32.4 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Ransom County, ND (Zone 4a) Short season
148 days
Last Spring Frost May 8
148 growing days
First Fall Frost October 3

Ransom County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 24 Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29
Recommended (50%) ✗ May not fit
Start indoors: Mar 6 Transplant: May 29 🍅 Harvest: Jul 31 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Mar 16 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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 106 gal / 100 sq ft
Tomatoes needs ~888 GDD — county provides 1,813 GDD Excellent fit

Tomatoes Planting Timeline โ€” Ransom County, ND

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors May 29 May 29 โ€“ Jun 12
Direct Sow May 22 May 22 โ€“ Jun 12
Harvest July 31 Jul 31 โ€“ Oct 9

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 Transplant Outdoors Direct Sow
July Harvest
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 4a

Growing Season

148 days

Growing Tips for Ransom 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 Ransom County, ND?

Ransom County is in Zone 4a with an average last frost of May 8. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ransom County, ND?

Ransom County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 8 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

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