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When to Plant Parsley in Roseau County, MN

Roseau County, Minnesota Zone 3b May

May in Roseau County, Minnesota — your action list

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 21
Avg. first frost September 22
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Move parsley into the garden

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Seed parsley outdoors

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

June will be here before you know it — start on
  • 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.

Roseau County, Minnesota is in USDA Zone 3b. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 655 feet, Roseau County receives approximately 32 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Parsley to ensure they mature before fall.

Roseau County, MN (Zone 3b) Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22
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Roseau County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (7 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jul 6 – Sep 7
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Jul 16 – Sep 17
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Jul 30 – Oct 1

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 Roseau County

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

Soil pH

Your soil pH (5.9–7.2) overlaps with Parsley's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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.

Succession Planting Parsley

2
successive plantings in your 124-day season

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

For a dedicated fall crop, sow by Jun 30.

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 2.6" 3.9" 0" ✅ Rainfall sufficient
Jun 2.6" 4.3" 0" ✅ Rainfall sufficient
Jul 2.6" 3.8" 0" ✅ Rainfall sufficient
Aug 2.6" 3.7" 0" ✅ Rainfall sufficient
Sep 2.6" 2.4" 0.2" 💧 Light watering
Oct 2.7" 0" ❄️ Dormant
Nov 1.9" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Roseau 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 ~648 GDD — county provides 1,147 GDD Excellent fit

Parsley Planting Timeline — Roseau County, MN

Parsley Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 14 May 14 – May 28
Direct Sow May 14 May 14 – Jun 4
Harvest July 16 Jul 16 – Sep 17
Fall Sowing June 30 Jun 30 – Jul 14

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors 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

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: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

124 days in Roseau County

Growing Tips for Parsley in Roseau County

Direct sow Parsley outdoors after May 21 in Roseau 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 Roseau County, MN?

Roseau County is in Zone 3b with an average last frost of May 21. Plan your Parsley planting based on this frost date — see the calendar above for exact timing.

What planting zone is Roseau County, MN?

Roseau County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 21 and first fall frost is September 22.

🌱

Your Roseau County Garden Planner — Free

A 24-page printable planner built for Roseau 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 Roseau 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.