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When to plant Potatoes in Cook County County,

Cook County County sits in cold Zone 3b. Plant Potatoes June 3–June 24 for the single annual harvest; the September 29 first frost closes the window.

When to Plant Potatoes in Cook County, MN

Potatoes
Cook County, Minnesota Zone 3b June

What to do in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Cook County, Minnesota.

Avg. last frost May 20
Avg. first frost September 29
Soil temp (4") 63°F
Watering Low
Pest pressure Moderate
Daylight 15.8 hrs
  1. Move potatoes into the garden

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Direct-sow potatoes

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

A few tasks this June that'll pay off in July
  • Starting indoors: potatoes

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

Cook County, Minnesota is in USDA Zone 3b. The average last spring frost is May 20 and the first fall frost is September 29, giving you a growing season of approximately 132 days.

At an elevation of 1,068 feet, Cook County receives approximately 34.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Potatoes to ensure they mature before fall.

Cook County, MN (Zone 3b) Short season
132 days
Last Spring Frost May 20
132 growing days
First Fall Frost September 29

Cook County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7.1

Drainage

Well Drained

Potatoes Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 13 Transplant: Jun 5 🍅 Harvest: Aug 14 – Oct 9
Recommended (50%) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 10 🍅 Harvest: Aug 19 – Oct 14
Safe Start (90%) ✗ May not fit
Start indoors: Mar 29 Transplant: Jun 21 🍅 Harvest: Aug 30 – Oct 25

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 Cook County

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

Soil pH

Your soil pH (6.1–7.1) is more alkaline than Potatoes prefers (5.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Potatoes will thrive.

How to Plant Potatoes

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

Succession Planting Potatoes

2
successive plantings in your 132-day season

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

Potatoes Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/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 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 1.4" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.5" 0" ❄️ Dormant
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 4.7" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 2.7" 0" ❄️ Dormant
Nov 2.5" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Cook County). Supplement amounts are based on average rainfall — 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" — 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.

Potatoes needs ~950 GDD — county provides 1,320 GDD Excellent fit

Potatoes Planting Timeline — Cook County, MN

Potatoes Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors June 10 Jun 10 – Jun 24
Direct Sow June 3 Jun 3 – Jun 24
Harvest August 19 Aug 19 – Oct 14

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

70–120 days

🧪 Soil pH

Needs 5–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 3b

📆 Growing Season

132 days in Cook County

Growing Tips for Potatoes in Cook County

Direct sow Potatoes outdoors after May 20 in Cook County when soil has warmed and frost danger has passed.

Your 132.0-day growing season in Cook County is tight for Potatoes (70.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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.

Recommended Potatoes Varieties for Cook County

Early-maturing potatoes for your season

Yukon Gold (65d) Red Norland (70d) Irish Cobbler (70d)

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 Cook County, MN?

Cook County is in Zone 3b with an average last frost of May 20. Plan your Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Cook County, MN?

Cook County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 20 and first fall frost is September 29.

When should I plant Potatoes in Cook County, ?

In Cook County, , plant Potatoes after the last frost (around May 20) and before the first frost (around September 29). Best results when soil holds above 50°F.

What growing zone is Cook County, for Potatoes?

Cook County sits in USDA Zone 3b. Potatoes grows reliably in zones 3a through 10b, so it's a good fit here.

Can Potatoes grow in Cook County's climate?

Yes — Potatoes grows well in Cook County's temperate climate. Cook County averages a 132-day frost-free season, with last frost around May 20 and first frost around September 29.

🌱

Your Cook County Garden Planner — Free

A 22-page printable planner built for Cook 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 Cook County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.