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When to Plant Celery in St. Louis County, MN

St. Louis County, Minnesota Zone 3b May

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

A quick May briefing for St. Louis County, Minnesota gardeners — what's urgent, what's next, and what can wait.

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. Sow celery where they'll grow

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

A few tasks this May that'll pay off in June
  • Transplants going out: celery
  • Fall sowing: celery

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Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

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 Celery 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) ✗ May not fit
Start indoors: Apr 16 Transplant: May 28 🍅 Harvest: Aug 20 – Oct 1
Recommended (50%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 2 🍅 Harvest: Aug 25 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: May 5 Transplant: Jun 16 🍅 Harvest: Sep 8 – Oct 20

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 Celery's growing requirements.

Soil pH

Your soil pH (6.0–7.0) is within Celery's preferred range (6.0–7.0).

Soil Texture

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

Drainage

Celery is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

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

How to Plant Celery

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 147 gal / 100 sq ft

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Celery 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 5.6" 5.1" 0.5" 💧 Light watering
Jul 5.6" 4.4" 1.2" 💧 Light watering
Aug 5.6" 3.7" 1.9" 💧 Light watering
Sep 5.6" 3.1" 2.5" 💧 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.

Celery 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.

Celery needs ~850 GDD — county provides 850 GDD Tight fit

Celery Planting Timeline — St. Louis County, MN

Celery Planting Calendar

Activity When Date Range
Start Indoors April 21 Apr 21 – May 5
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 26 May 26 – Jun 16
Harvest August 25 Aug 25 – Oct 6
Fall Sowing June 18 Jun 18 – Jul 2

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 3b

📆 Growing Season

100 days in St. Louis County

Growing Tips for Celery in St. Louis County

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

Your 100.0-day growing season in St. Louis County is tight for Celery (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

St. Louis County is in Zone 3b with an average last frost of June 2. Plan your Celery 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.