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When to Plant Parsley in St. Louis County, MN

St. Louis County, Minnesota Zone 3b May

Your May game plan for St. Louis County, Minnesota

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. Set out parsley seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Direct-sow parsley

    Your soil is 49°F — warm enough for these to germinate without babying.

June prep starts now
  • Fall sowing: parsley

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Parsley is a biennial herb available in flat-leaf (Italian) and curly varieties. It is a nutritional powerhouse rich in vitamins C and K and adds fresh flavor to countless dishes.

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 Parsley 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

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 21 🍅 Harvest: Jul 23 – Sep 24
Recommended (50%) ✗ May not fit
Start indoors: Apr 21 Transplant: May 26 🍅 Harvest: Jul 28 – Sep 29
Safe Start (90%) ✗ May not fit
Start indoors: May 5 Transplant: Jun 9 🍅 Harvest: Aug 11 – Oct 13

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 Parsley's growing requirements.

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Parsley.

Organic Matter

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

How to Plant Parsley

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

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

Plant Water Budget

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

Monthly Watering Guide for Parsley

Parsley needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Parsley 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 2.6" 5.1" 0" ✅ Rainfall sufficient
Jul 2.6" 4.4" 0" ✅ Rainfall sufficient
Aug 2.6" 3.7" 0" ✅ Rainfall sufficient
Sep 2.6" 3.1" 0" ✅ Rainfall sufficient
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.

Parsley 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.

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

Parsley Planting Timeline — St. Louis County, MN

Parsley Planting Calendar

Activity When Date Range
Start Indoors April 21 Apr 21 – May 5
Transplant Outdoors May 26 May 26 – Jun 9
Direct Sow May 26 May 26 – Jun 16
Harvest July 28 Jul 28 – Sep 29
Fall Sowing June 18 Jun 18 – Jul 2

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 3b

📆 Growing Season

100 days in St. Louis County

Growing Tips for Parsley in St. Louis County

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

Common pests for Parsley 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 6-8 weeks before last frost. Soak seeds overnight as germination is slow. Harvest outer stems first to keep plants productive. Parsley attracts swallowtail butterflies.

Companion Planting

Good Companions

Avoid Planting Near

  • Mint
  • Lettuce

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

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

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