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When to Plant Sunflower in Presque Isle County, MI

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.

Presque Isle County, Michigan is in USDA Zone 4b. The average last spring frost is May 17 and the first fall frost is October 9, giving you a growing season of approximately 145 days.

At an elevation of 1,392 feet, Presque Isle County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Sunflower to ensure they mature before fall.

Presque Isle County, MI (Zone 4b) Short season
145 days
Last Spring Frost May 17
145 growing days
First Fall Frost October 9

Presque Isle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 8 Transplant: May 31 🍅 Harvest: Aug 9 – Sep 27
Recommended (50%) ✓ Fits season (5 days to spare)
Start indoors: Mar 15 Transplant: Jun 7 🍅 Harvest: Aug 16 – Oct 4
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Apr 7 Transplant: Jun 30 🍅 Harvest: Sep 8 – Oct 27

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 Presque Isle County

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

Soil pH

Your soil pH (5.9โ€“6.7) overlaps with Sunflower's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

The silt loam soil in Presque Isle County is excellent for Sunflower โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Sunflower.

How to Plant Sunflower

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

Succession Planting Sunflower

2
successive plantings in your 145-day season

Sow every 8 weeks. Last sowing by Jul 01 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.2″/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 โ€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.9" 0" โ„๏ธ Dormant
Mar โ€” 3.2" 0" โ„๏ธ Dormant
Apr โ€” 4.2" 0" โ„๏ธ Dormant
May 2.2" 4.7" 0" โœ… Rainfall sufficient
Jun 2.2" 4.7" 0" โœ… Rainfall sufficient
Jul 2.2" 4.7" 0" โœ… Rainfall sufficient
Aug 2.2" 4.6" 0" โœ… Rainfall sufficient
Sep 2.2" 3.2" 0" โœ… Rainfall sufficient
Oct 2.2" 3.2" 0" โœ… Rainfall sufficient
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Presque Isle County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~1,105 GDD — county provides 1,885 GDD Excellent fit

Sunflower Planting Timeline โ€” Presque Isle County, MI

Sunflower Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 โ€“ Mar 29
Transplant Outdoors June 7 Jun 7 โ€“ Jun 21
Direct Sow May 31 May 31 โ€“ Jun 21
Harvest August 16 Aug 16 โ€“ Oct 4

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“100 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

145 days in Presque Isle County

Growing Tips for Sunflower in Presque Isle County

Direct sow Sunflower outdoors after May 17 in Presque Isle 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 Presque Isle County, MI?

Presque Isle County is in Zone 4b with an average last frost of May 17. Plan your Sunflower planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Presque Isle County, MI?

Presque Isle County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 17 and first fall frost is October 9.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Presque Isle County, MI. Local conditions may vary. Last updated: April 2026.