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When to Plant Pole Beans in Ontonagon County, MI

Pole beans are climbing varieties of green beans that produce over a much longer season than bush types. They require trellising but yield more per square foot.

Ontonagon County, Michigan is in USDA Zone 4a. The average last spring frost is May 22 and the first fall frost is September 28, giving you a growing season of approximately 129 days.

At an elevation of 502 feet, Ontonagon County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Pole Beans to ensure they mature before fall.

Ontonagon County, MI (Zone 4a) Short season
129 days
Last Spring Frost May 22
129 growing days
First Fall Frost September 28

Ontonagon County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 16 Transplant: Jun 8 🍅 Harvest: Aug 3 – Sep 28
Recommended (50%) ✗ May not fit
Start indoors: Mar 20 Transplant: Jun 12 🍅 Harvest: Aug 7 – Oct 2
Safe Start (90%) ✗ May not fit
Start indoors: Apr 4 Transplant: Jun 27 🍅 Harvest: Aug 22 – Oct 17

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 Ontonagon County

How your county's soil matches Pole Beans's growing requirements.

Soil pH

Your soil pH (6.2โ€“7.2) overlaps with Pole Beans's range (6.0โ€“7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) โ€” Pole Beans will thrive.

How to Plant Pole Beans

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

Succession Planting Pole Beans

2
successive plantings in your 129-day season

Sow every 6.3 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.4″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Pole Beans

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

Month Pole Beans Needs Rainfall You Supplement Action
Jan โ€” 2" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar โ€” 2.8" 0" โ„๏ธ Dormant
Apr โ€” 4.4" 0" โ„๏ธ Dormant
May 4.3" 4.8" 0" โœ… Rainfall sufficient
Jun 4.3" 5.2" 0" โœ… Rainfall sufficient
Jul 4.3" 4.3" 0" โœ… Rainfall sufficient
Aug 4.3" 4.2" 0.1" ๐Ÿ’ง Light watering
Sep 4.3" 3.5" 0.8" ๐Ÿ’ง Light watering
Oct โ€” 3.6" 0" โ„๏ธ Dormant
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

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

Pole Beans 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.

Pole Beans needs ~625 GDD — county provides 1,290 GDD Excellent fit

Pole Beans Planting Timeline โ€” Ontonagon County, MI

Pole Beans Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 โ€“ Apr 3
Transplant Outdoors June 12 Jun 12 โ€“ Jun 26
Direct Sow June 5 Jun 5 โ€“ Jun 26
Harvest August 7 Aug 7 โ€“ Oct 2

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Start Indoors
May โ€”
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

55โ€“70 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

129 days in Ontonagon County

Growing Tips for Pole Beans in Ontonagon County

Direct sow Pole Beans outdoors after May 22 in Ontonagon County when soil has warmed and frost danger has passed.

Common pests for Pole Beans in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Provide sturdy 6-8 foot poles, tepees, or trellises. Direct sow after last frost. Pick regularly to encourage continued production. Beans fix nitrogen benefiting following crops.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic
  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pole Beans in Ontonagon County, MI?

Ontonagon County is in Zone 4a with an average last frost of May 22. Plan your Pole Beans planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Ontonagon County, MI?

Ontonagon County, Michigan is in USDA Hardiness Zone 4a. The average last spring frost is May 22 and first fall frost is September 28.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Ontonagon County gardeners in Zone 4a 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 Ontonagon County, MI. Local conditions may vary. Last updated: April 2026.