Blog

When to Plant Tomatoes in Nelson 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.

Nelson County, North Dakota is in USDA Zone 3b. The average last spring frost is May 12 and the first fall frost is September 27, giving you a growing season of approximately 138 days.

At an elevation of 547 feet, Nelson County receives approximately 33.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Nelson County, ND (Zone 3b) Short season
138 days
Last Spring Frost May 12
138 growing days
First Fall Frost September 27

Nelson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 6 Transplant: May 29 🍅 Harvest: Jul 31 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Mar 10 Transplant: Jun 2 🍅 Harvest: Aug 4 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: Mar 21 Transplant: Jun 13 🍅 Harvest: Aug 15 – Oct 17

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 Nelson County

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

Soil pH

Your soil pH (6.6โ€“7.8) is more alkaline than Tomatoes prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) โ€” Tomatoes will thrive.

How to Plant Tomatoes

0.5"
Planting Depth
24"
Between Plants
36"
Between Rows

Succession Planting Tomatoes

2
successive plantings in your 138-day season

Sow every 6.9 weeks. Last sowing by Jul 04 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.0″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 229 gal / 100 sq ft

Monthly Watering Guide for Tomatoes

Tomatoes needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Tomatoes Needs Rainfall You Supplement Action
Jan โ€” 0.9" 0" โ„๏ธ Dormant
Feb โ€” 1.1" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr โ€” 3.3" 0" โ„๏ธ Dormant
May 5.2" 4.6" 0.6" ๐Ÿ’ง Light watering
Jun 5.2" 5.8" 0" โœ… Rainfall sufficient
Jul 5.2" 3.9" 1.3" ๐Ÿ’ง Light watering
Aug 5.2" 4.1" 1.1" ๐Ÿ’ง Light watering
Sep 5.2" 3.5" 1.7" ๐Ÿ’ง Light watering
Oct โ€” 2" 0" โ„๏ธ Dormant
Nov โ€” 1.2" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

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

Tomatoes 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.

Tomatoes needs ~725 GDD — county provides 1,380 GDD Excellent fit

Tomatoes Planting Timeline โ€” Nelson County, ND

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors June 2 Jun 2 โ€“ Jun 16
Direct Sow May 26 May 26 โ€“ Jun 16
Harvest August 4 Aug 4 โ€“ Oct 6

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.2"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 3b

๐Ÿ“† Growing Season

138 days in Nelson County

Growing Tips for Tomatoes in Nelson County

Direct sow Tomatoes outdoors after May 12 in Nelson County when soil has warmed and frost danger has passed.

Common pests for Tomatoes 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. Bury transplants deep to encourage rooting along the stem. Provide consistent moisture to prevent blossom end rot and cracking.

Recommended Tomatoes Varieties for Nelson County

Choose determinate, early-maturing varieties for your short season

Early Girl (52d) Stupice (55d) Glacier (55d) Sub Arctic Plenty (45d)

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Fennel
  • Potatoes

Check more plant combinations with our Companion Planting Checker →

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 Nelson County, ND?

Nelson County is in Zone 3b with an average last frost of May 12. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Nelson County, ND?

Nelson County, North Dakota is in USDA Hardiness Zone 3b. The average last spring frost is May 12 and first fall frost is September 27.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Nelson County gardeners in Zone 3b 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 Nelson County, ND. Local conditions may vary. Last updated: April 2026.