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When to Plant Celery in Ontonagon County, MI

Ontonagon County, Michigan Zone 4b May

Top priorities for Ontonagon County, Michigan gardeners in May

Welcome to May in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 22
Avg. first frost September 28
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Transplant celery outside

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

  2. Plant celery from seed, right in the garden

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

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Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Ontonagon County, Michigan is in USDA Zone 4b. 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 80°F, so choose short-season varieties of Celery to ensure they mature before fall.

Ontonagon County, MI (Zone 4b) Short season
129 days
Last Spring Frost May 22
129 growing days
First Fall Frost September 28
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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: Apr 6 Transplant: May 18 🍅 Harvest: Aug 10 – Oct 5
Recommended (50%) ✗ May not fit
Start indoors: Apr 10 Transplant: May 22 🍅 Harvest: Aug 14 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Apr 25 Transplant: Jun 6 🍅 Harvest: Aug 29 – Oct 24

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 Celery's growing requirements.

Soil pH

Your soil pH (6.2–7.2) overlaps with Celery's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Celery will thrive.

How to Plant Celery

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

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Celery Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 2.1" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.4" 0" ❄️ Dormant
May 5.6" 4.8" 0.8" 💧 Light watering
Jun 5.6" 5.2" 0.4" 💧 Light watering
Jul 5.6" 4.3" 1.3" 💧 Light watering
Aug 5.6" 4.2" 1.4" 💧 Light watering
Sep 5.6" 3.5" 2.1" 💧 Light watering
Oct 3.6" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Celery 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.

Celery needs ~1,000 GDD — county provides 1,290 GDD Good fit

Celery Planting Timeline — Ontonagon County, MI

Celery Planting Calendar

Activity When Date Range
Start Indoors April 10 Apr 10 – Apr 24
Transplant Outdoors May 22 May 22 – Jun 5
Direct Sow May 15 May 15 – Jun 5
Harvest August 14 Aug 14 – Oct 9
Fall Sowing July 6 Jul 6 – Jul 20

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Natural rainfall sufficient

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

129 days in Ontonagon County

Growing Tips for Celery in Ontonagon County

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

Your 129.0-day growing season in Ontonagon County is tight for Celery (80.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Celery in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celery in Ontonagon County, MI?

Ontonagon County is in Zone 4b with an average last frost of May 22. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ontonagon County, MI?

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

🌱

Your Ontonagon County Garden Planner — Free

A 24-page printable planner built for Ontonagon County (Zone 4b). 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 Ontonagon 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.