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When to Plant Sorrel in Koochiching County, MN

Koochiching County, Minnesota Zone 3b May

Koochiching County, Minnesota gardeners: here's your May plan

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

Avg. last frost May 22
Avg. first frost September 18
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Plant out sorrel

    Frost risk is low now in Koochiching County, Minnesota. If you've been covering beds overnight, you can stop.

  2. Scatter sorrel into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

June prep starts now
  • First harvests: sorrel
  • Fall sowing: sorrel

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Sorrel is a perennial herb with tangy, lemon-flavored arrow-shaped leaves. It is one of the first greens to emerge in spring and is used in soups and salads.

Koochiching County, Minnesota is in USDA Zone 3b. The average last spring frost is May 22 and the first fall frost is September 18, giving you a growing season of approximately 119 days.

At an elevation of 508 feet, Koochiching County receives approximately 41.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Sorrel to ensure they mature before fall.

Koochiching County, MN (Zone 3b) Short season
119 days
Last Spring Frost May 22
119 growing days
First Fall Frost September 18
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Koochiching County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (21 days to spare)
Start indoors: Apr 4 Transplant: May 9 🍅 Harvest: Jun 20 – Aug 22
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Jun 26 – Aug 28
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: May 4 Transplant: Jun 8 🍅 Harvest: Jul 20 – Sep 21

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 Koochiching County

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

Soil pH

Your soil pH (5.8–7.2) overlaps with Sorrel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Sorrel.

How to Plant Sorrel

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 Sorrel

3
successive plantings in your 119-day season

Sow every 4.6 weeks. Last sowing by Jul 20 to harvest before frost.

For a dedicated fall crop, sow by Jun 26.

Plant Water Budget

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

Monthly Watering Guide for Sorrel

Sorrel needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sorrel Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 4" 0" ❄️ Dormant
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 2.8" 0" ❄️ Dormant
Nov 3.2" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Sorrel 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.

Sorrel needs ~462 GDD — county provides 1,100 GDD Excellent fit

Sorrel Planting Timeline — Koochiching County, MN

Sorrel Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 15 May 15 – May 29
Direct Sow May 15 May 15 – Jun 5
Harvest June 26 Jun 26 – Aug 28
Fall Sowing June 26 Jun 26 – Jul 10

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 Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

119 days in Koochiching County

Growing Tips for Sorrel in Koochiching County

Direct sow Sorrel outdoors after May 22 in Koochiching County when soil has warmed and frost danger has passed.

General growing tips

Direct sow in early spring or fall. Remove flower stalks promptly to encourage leaf production. Divide clumps every 3-4 years. Young leaves have the best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sorrel in Koochiching County, MN?

Koochiching County is in Zone 3b with an average last frost of May 22. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Koochiching County, MN?

Koochiching County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 22 and first fall frost is September 18.

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Your Koochiching County Garden Planner — Free

A 24-page printable planner built for Koochiching 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 Koochiching 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.