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When to Plant Carrots in St. Louis County, MN

St. Louis County, Minnesota Zone 3b May

Top priorities for St. Louis County, Minnesota gardeners in May

We've pulled the most time-sensitive tasks for St. Louis County, Minnesota this May and put them front and centre. Tackle them in order.

Avg. last frost June 2
Avg. first frost September 10
Soil temp (4") 49°F
Watering Low
Pest pressure Low
Daylight 14.9 hrs
  1. Scatter carrots into prepared beds

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

A few tasks this May that'll pay off in June
  • Fall sowing: carrots

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Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

St. Louis County, Minnesota is in USDA Zone 3b. The average last spring frost is June 2 and the first fall frost is September 10, giving you a growing season of approximately 100 days.

At an elevation of 531 feet, St. Louis County receives approximately 36.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Carrots to ensure they mature before fall.

St. Louis County, MN (Zone 3b) Short season
100 days
Last Spring Frost June 2
100 growing days
First Fall Frost September 10
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St. Louis County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Transplant: May 28 🍅 Harvest: Jul 30 – Sep 3
Recommended (50%) ✓ Fits season (2 days to spare)
Transplant: Jun 2 🍅 Harvest: Aug 4 – Sep 8
Safe Start (90%) ✓ Fits season (0 days to spare)
Transplant: Jun 16 🍅 Harvest: Aug 18 – Sep 22

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 St. Louis County

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

Soil pH

Your soil pH (6.0–7.0) overlaps with Carrots's range (6.0–6.8), though not a perfect match.

Soil Texture

The silt loam soil in St. Louis County is excellent for Carrots — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Carrots.

Organic Matter

Organic matter is excellent (4.0%) — Carrots will thrive.

How to Plant Carrots

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Carrots

Carrots needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Carrots Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.2" 0" ❄️ Dormant
May 3.9" 0" ❄️ Dormant
Jun 3.5" 5.1" 0" ✅ Rainfall sufficient
Jul 3.5" 4.4" 0" ✅ Rainfall sufficient
Aug 3.5" 3.7" 0" ✅ Rainfall sufficient
Sep 3.5" 3.1" 0.4" 💧 Light watering
Oct 2.8" 0" ❄️ Dormant
Nov 2.3" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in St. Louis County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Carrots 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" — every day above 50°F 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.

Carrots needs ~595 GDD — county provides 850 GDD Excellent fit

Carrots Planting Timeline — St. Louis County, MN

Carrots Planting Calendar

Activity When Date Range
Direct Sow May 26 May 26 – Jun 16
Harvest July 28 Jul 28 – Sep 1
Fall Sowing June 18 Jun 18 – Jul 2

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Direct Sow
June Direct Sow Fall Sowing
July Fall Sowing Harvest
August Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

100 days in St. Louis County

Growing Tips for Carrots in St. Louis County

Direct sow Carrots outdoors after June 02 in St. Louis County when soil has warmed and frost danger has passed.

Common pests for Carrots in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Recommended Carrots Varieties for St. Louis County

Fast-maturing varieties for your season

Adelaide (50d) Mokum (54d) Nelson (56d)

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.

Frequently Asked Questions

When should I plant Carrots in St. Louis County, MN?

St. Louis County is in Zone 3b with an average last frost of June 2. Plan your Carrots planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Louis County, MN?

St. Louis County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is June 2 and first fall frost is September 10.

🌱

Your St. Louis County Garden Planner — Free

A 24-page printable planner built for St. Louis County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.