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When to Plant Lettuce in Roseau County, MN

Roseau County, Minnesota Zone 3b May

Top priorities for Roseau County, Minnesota gardeners in May

Your garden in Roseau County, Minnesota is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 21
Avg. first frost September 22
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Time to transplant lettuce

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Outdoor sowing time: lettuce

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

To set up a strong June, finish these tasks
  • First harvests: lettuce
  • Fall sowing: lettuce

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Lettuce is a fast-growing cool-season green available in leaf, romaine, butterhead, and crisphead types. It is the foundation of salads and one of the easiest crops to grow.

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 Lettuce 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 (21 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Jun 15 – Aug 24
Recommended (50%) ✓ Fits season (19 days to spare)
Start indoors: Apr 9 Transplant: May 21 🍅 Harvest: Jun 25 – Sep 3
Safe Start (90%) ✓ Fits season (21 days to spare)
Start indoors: Apr 23 Transplant: Jun 4 🍅 Harvest: Jul 9 – Sep 17

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 Lettuce's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Lettuce will thrive.

How to Plant Lettuce

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

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

Succession Planting Lettuce

4
successive plantings in your 124-day season

Sow every 3.4 weeks. Last sowing by Jul 24 to harvest before frost.

For a dedicated fall crop, sow by Jun 30.

Plant Water Budget

Plant needs
0.7″/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 Lettuce

Lettuce needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Lettuce 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 3" 3.9" 0" ✅ Rainfall sufficient
Jun 3" 4.3" 0" ✅ Rainfall sufficient
Jul 3" 3.8" 0" ✅ Rainfall sufficient
Aug 3" 3.7" 0" ✅ Rainfall sufficient
Sep 3" 2.4" 0.6" 💧 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.

Lettuce 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.

Lettuce needs ~416 GDD — county provides 1,147 GDD Excellent fit

Lettuce Planting Timeline — Roseau County, MN

Lettuce Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 14 May 14 – Jun 4
Harvest June 25 Jun 25 – Sep 3
Fall Sowing June 30 Jun 30 – Jul 14

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

30–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

124 days in Roseau County

Growing Tips for Lettuce in Roseau County

Direct sow Lettuce outdoors after May 21 in Roseau County when soil has warmed and frost danger has passed.

Common pests for Lettuce in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly every 2 weeks for continuous harvest. Provide afternoon shade in warm weather to delay bolting. Harvest in the morning for crispest leaves.

Recommended Lettuce Varieties for Roseau County

Fast-maturing leaf and butterhead types

Salad Bowl (40d) Black Seeded Simpson (45d) Buttercrunch (50d)

Companion Planting

Good Companions

Avoid Planting Near

  • Celery

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Lettuce Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let plants bolt and flower. Harvest seed heads when fluffy.
Storage Store airtight; viable 6 years at 35°F, under 45% humidity.

Very easy to save. Let a few plants bolt each season.

Frequently Asked Questions

When should I plant Lettuce in Roseau County, MN?

Roseau County is in Zone 3b with an average last frost of May 21. Plan your Lettuce 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.