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When to Plant Sweet Potatoes in Charlevoix County, MI

Charlevoix County, Michigan Zone 6a May

Your May game plan for Charlevoix County, Michigan

Welcome to May in Zone 6a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 5
Avg. first frost October 21
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move sweet potatoes into the garden

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant sweet potatoes from seed, right in the garden

    These tolerate cool soil, so you're not gambling by sowing now.

June prep starts now
  • Starting indoors: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Charlevoix County, Michigan is in USDA Zone 6a. The average last spring frost is May 5 and the first fall frost is October 21, giving you a growing season of approximately 169 days.

At an elevation of 821 feet, Charlevoix County receives approximately 41.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Sweet Potatoes to ensure they mature before fall.

Charlevoix County, MI (Zone 6a) Moderate season
169 days
Last Spring Frost May 5
169 growing days
First Fall Frost October 21
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Charlevoix County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (10 days to spare)
Start indoors: Mar 2 Transplant: May 11 🍅 Harvest: Aug 10 – Sep 28
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 10 Transplant: May 19 🍅 Harvest: Aug 18 – Oct 6
Safe Start (90%) ✓ Fits season (15 days to spare)
Start indoors: Mar 25 Transplant: Jun 3 🍅 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 Charlevoix County

How your county's soil matches Sweet Potatoes's growing requirements.

Soil pH

Your soil pH (6.0–6.8) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Sweet Potatoes will thrive.

How to Plant Sweet Potatoes

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/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 Sweet Potatoes

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

Month Sweet Potatoes Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 4.3" 5.3" 0" ✅ Rainfall sufficient
Jun 4.3" 5.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.7" 0" ✅ Rainfall sufficient
Sep 4.3" 4.1" 0.2" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

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

Sweet Potatoes 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.

Sweet Potatoes needs ~1,365 GDD — county provides 2,197 GDD Excellent fit

Sweet Potatoes Planting Timeline — Charlevoix County, MI

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 12 May 12 – Jun 2
Harvest August 18 Aug 18 – Oct 6

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6a

📆 Growing Season

169 days in Charlevoix County

Growing Tips for Sweet Potatoes in Charlevoix County

Direct sow Sweet Potatoes outdoors after May 05 in Charlevoix County when soil has warmed and frost danger has passed.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Charlevoix County, MI?

Charlevoix County is in Zone 6a with an average last frost of May 5. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Charlevoix County, MI?

Charlevoix County, Michigan is in USDA Hardiness Zone 6a. The average last spring frost is May 5 and first fall frost is October 21.

🌱

Your Charlevoix County Garden Planner — Free

A 24-page printable planner built for Charlevoix County (Zone 6a). 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 Charlevoix County, MI. 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.