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When to Plant Potatoes in Schoolcraft County, MI

Potatoes are a versatile staple crop that produces tubers underground. They come in hundreds of varieties with varying colors, textures, and maturity dates.

Schoolcraft County, Michigan is in USDA Zone 4b. The average last spring frost is May 14 and the first fall frost is October 12, giving you a growing season of approximately 151 days.

At an elevation of 1,121 feet, Schoolcraft County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Potatoes to ensure they mature before fall.

Schoolcraft County, MI (Zone 4b) Moderate season
151 days
Last Spring Frost May 14
151 growing days
First Fall Frost October 12

Schoolcraft County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 5 Transplant: May 28 🍅 Harvest: Aug 6 – Oct 15
Recommended (50%) ✗ May not fit
Start indoors: Mar 12 Transplant: Jun 4 🍅 Harvest: Aug 13 – Oct 22
Safe Start (90%) ✗ May not fit
Start indoors: Mar 25 Transplant: Jun 17 🍅 Harvest: Aug 26 – Nov 4

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 Schoolcraft County

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

Soil pH

Your soil pH (6.0โ€“7.0) overlaps with Potatoes's range (5.0โ€“6.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) โ€” Potatoes will thrive.

How to Plant Potatoes

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

Succession Planting Potatoes

2
successive plantings in your 151-day season

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

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

Monthly Watering Guide for Potatoes

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 Potatoes Needs Rainfall You Supplement Action
Jan โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.5" 0" โ„๏ธ Dormant
Apr โ€” 3.4" 0" โ„๏ธ Dormant
May 4.3" 4.5" 0" โœ… Rainfall sufficient
Jun 4.3" 4.4" 0" โœ… Rainfall sufficient
Jul 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Aug 4.3" 4" 0.3" ๐Ÿ’ง Light watering
Sep 4.3" 3.1" 1.2" ๐Ÿ’ง Light watering
Oct 4.3" 3" 1.3" ๐Ÿ’ง Light watering
Nov โ€” 2.5" 0" โ„๏ธ Dormant
Dec โ€” 2.2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Schoolcraft County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

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" 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.

Potatoes needs ~1,092 GDD — county provides 1,736 GDD Excellent fit

Potatoes Planting Timeline โ€” Schoolcraft County, MI

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 12 Mar 12 โ€“ Mar 26
Transplant Outdoors June 4 Jun 4 โ€“ Jun 18
Direct Sow May 28 May 28 โ€“ Jun 18
Harvest August 13 Aug 13 โ€“ Oct 22

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

1"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“120 days

๐Ÿงช Soil pH

Needs 5โ€“6.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4b

๐Ÿ“† Growing Season

151 days in Schoolcraft County

Growing Tips for Potatoes in Schoolcraft County

Direct sow Potatoes outdoors after May 14 in Schoolcraft County when soil has warmed and frost danger has passed.

Common pests for Potatoes in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant seed potatoes (not grocery store potatoes) 4 inches deep in spring. Hill soil around stems as plants grow to prevent greening. Stop watering when plants die back.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Cucumber
  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Potatoes in Schoolcraft County, MI?

Schoolcraft County is in Zone 4b with an average last frost of May 14. Plan your Potatoes planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Schoolcraft County, MI?

Schoolcraft County, Michigan is in USDA Hardiness Zone 4b. The average last spring frost is May 14 and first fall frost is October 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Schoolcraft 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 Schoolcraft County, MI. Local conditions may vary. Last updated: April 2026.