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When to Plant Tomatoes in Beltrami County, MN

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.

Beltrami County, Minnesota is in USDA Zone 3b. The average last spring frost is May 16 and the first fall frost is September 28, giving you a growing season of approximately 135 days.

At an elevation of 1,023 feet, Beltrami County receives approximately 39.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Tomatoes to ensure they mature before fall.

Beltrami County, MN (Zone 3b) Short season
135 days
Last Spring Frost May 16
135 growing days
First Fall Frost September 28

Beltrami County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 8 Transplant: May 31 🍅 Harvest: Aug 2 – Oct 4
Recommended (50%) ✗ May not fit
Start indoors: Mar 14 Transplant: Jun 6 🍅 Harvest: Aug 8 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 26 🍅 Harvest: Aug 28 – Oct 30

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 Beltrami County

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

Soil pH

Your soil pH (5.9โ€“7.0) overlaps with Tomatoes's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) 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 135-day season

Sow every 6.9 weeks. Last sowing by Jul 05 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 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€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.8" 0" โ„๏ธ Dormant
Mar โ€” 2.7" 0" โ„๏ธ Dormant
Apr โ€” 3.6" 0" โ„๏ธ Dormant
May 5.2" 4.6" 0.6" ๐Ÿ’ง Light watering
Jun 5.2" 5.2" 0" โœ… Rainfall sufficient
Jul 5.2" 4.6" 0.6" ๐Ÿ’ง Light watering
Aug 5.2" 4.2" 1" ๐Ÿ’ง Light watering
Sep 5.2" 3.4" 1.8" ๐Ÿ’ง Light watering
Oct โ€” 3.2" 0" โ„๏ธ Dormant
Nov โ€” 2.4" 0" โ„๏ธ Dormant
Dec โ€” 1.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Beltrami 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 ~671 GDD — county provides 1,248 GDD Excellent fit

Tomatoes Planting Timeline โ€” Beltrami County, MN

Tomatoes Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 โ€“ Mar 28
Transplant Outdoors June 6 Jun 6 โ€“ Jun 20
Direct Sow May 30 May 30 โ€“ Jun 20
Harvest August 8 Aug 8 โ€“ Oct 10

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 Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“85 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 3b

๐Ÿ“† Growing Season

135 days in Beltrami County

Growing Tips for Tomatoes in Beltrami County

Direct sow Tomatoes outdoors after May 16 in Beltrami 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 Beltrami 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 Beltrami County, MN?

Beltrami County is in Zone 3b with an average last frost of May 16. Plan your Tomatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Beltrami County, MN?

Beltrami County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 16 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Beltrami 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 Beltrami County, MN. Local conditions may vary. Last updated: April 2026.