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When to Plant Sunflower in Yellow Medicine County, MN

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.

Yellow Medicine County, Minnesota is in USDA Zone 4a. The average last spring frost is April 30 and the first fall frost is October 4, giving you a growing season of approximately 157 days.

At an elevation of 1,382 feet, Yellow Medicine County receives approximately 34 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Sunflower to ensure they mature before fall.

Yellow Medicine County, MN (Zone 4a) Moderate season
157 days
Last Spring Frost April 30
157 growing days
First Fall Frost October 4

Yellow Medicine County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Feb 21 Transplant: May 16 🍅 Harvest: Jul 25 – Sep 12
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Feb 26 Transplant: May 21 🍅 Harvest: Jul 30 – Sep 17
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Mar 13 Transplant: Jun 5 🍅 Harvest: Aug 14 – Oct 2

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.

Plant Water Budget

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

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Sunflower needs ~978 GDD — county provides 1,805 GDD Excellent fit

Sunflower Planting Timeline โ€” Yellow Medicine County, MN

Sunflower Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 โ€“ Mar 12
Transplant Outdoors May 21 May 21 โ€“ Jun 4
Direct Sow May 14 May 14 โ€“ Jun 4
Harvest July 30 Jul 30 โ€“ Sep 17

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“100 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 4a

Growing Season

157 days

Growing Tips for Yellow Medicine County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Sunflower in Yellow Medicine County, MN?

Yellow Medicine County is in Zone 4a with an average last frost of April 30. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Yellow Medicine County, MN?

Yellow Medicine County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is April 30 and first fall frost is October 4.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Yellow Medicine County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

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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 Yellow Medicine County, MN. Local conditions may vary. Last updated: April 2026.