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When to Plant Sunflower in Lake of the Woods County, MN

Lake of the Woods County, Minnesota Zone 3b May

Your May game plan for Lake of the Woods County, Minnesota

Your Lake of the Woods County, Minnesota garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 19
Avg. first frost September 22
Soil temp (4") 52°F
Watering Low
Pest pressure Low
Daylight 15 hrs
June prep starts now
  • Transplants going out: sunflower
  • Direct-sowing: sunflower

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Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.

Lake of the Woods County, Minnesota is in USDA Zone 3b. The average last spring frost is May 19 and the first fall frost is September 22, giving you a growing season of approximately 126 days.

At an elevation of 1,032 feet, Lake of the Woods County receives approximately 32.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Sunflower to ensure they mature before fall.

Lake of the Woods County, MN (Zone 3b) Short season
126 days
Last Spring Frost May 19
126 growing days
First Fall Frost September 22

Lake of the Woods County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 1
Recommended (50%) ✗ May not fit
Start indoors: Mar 17 Transplant: Jun 9 🍅 Harvest: Aug 18 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 24 🍅 Harvest: Sep 2 – Oct 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 Lake of the Woods County

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

Soil pH

Your soil pH (5.7–7.2) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Lake of the Woods County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Sunflower.

Organic Matter

Organic matter is excellent (5.0%) — Sunflower will thrive.

How to Plant Sunflower

1"
Planting Depth
18"
Between Plants
30"
Between Rows

Succession Planting Sunflower

2
successive plantings in your 126-day season

Sow every 8 weeks. Last sowing by Jun 14 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Sunflower

Sunflower needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sunflower Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 2.2" 4.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4" 0" ✅ Rainfall sufficient
Jul 2.2" 3.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.3" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

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

Sunflower 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.

Sunflower needs ~850 GDD — county provides 1,260 GDD Excellent fit

Sunflower Planting Timeline — Lake of the Woods County, MN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors June 9 Jun 9 – Jun 23
Direct Sow June 2 Jun 2 – Jun 23
Harvest August 18 Aug 18 – Oct 6

Plant 1" deep · 18" apart · Rows 30" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 3b

📆 Growing Season

126 days in Lake of the Woods County

Growing Tips for Sunflower in Lake of the Woods County

Direct sow Sunflower outdoors after May 19 in Lake of the Woods County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sunflower in Lake of the Woods County, MN?

Lake of the Woods County is in Zone 3b with an average last frost of May 19. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake of the Woods County, MN?

Lake of the Woods County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 19 and first fall frost is September 22.

🌱

Your Lake of the Woods County Garden Planner — Free

A 24-page printable planner built for Lake of the Woods 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 Lake of the Woods 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.