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When to Plant Celery in Iosco County, MI

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.

Iosco County, Michigan is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is October 3, giving you a growing season of approximately 142 days.

At an elevation of 696 feet, Iosco County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88ยฐF, providing good warmth for Celery during the growing season.

Iosco County, MI (Zone 5a) Short season
142 days
Last Spring Frost May 14
142 growing days
First Fall Frost October 3

Iosco County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (3 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Jul 31 – Sep 25
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Aug 6 – Oct 1
Safe Start (90%) ✓ Fits season (2 days to spare)
Start indoors: Apr 23 Transplant: May 28 🍅 Harvest: Aug 20 – Oct 15

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 Iosco County

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

Soil pH

Your soil pH (6.2โ€“6.9) is within Celery's preferred range (6.0โ€“7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) โ€” Celery will thrive.

How to Plant Celery

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.1″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 241 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 โ€” 1.7" 0" โ„๏ธ Dormant
Feb โ€” 1.6" 0" โ„๏ธ Dormant
Mar โ€” 2.9" 0" โ„๏ธ Dormant
Apr โ€” 3.8" 0" โ„๏ธ Dormant
May 5.6" 4.7" 0.9" ๐Ÿ’ง Light watering
Jun 5.6" 4.7" 0.9" ๐Ÿ’ง Light watering
Jul 5.6" 3.6" 2" ๐Ÿ’ง Light watering
Aug 5.6" 4" 1.6" ๐Ÿ’ง Light watering
Sep 5.6" 2.9" 2.7" ๐Ÿ’ง Light watering
Oct 5.6" 2.7" 2.9" ๐Ÿšฟ Regular watering
Nov โ€” 2.8" 0" โ„๏ธ Dormant
Dec โ€” 2" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Oct in Iosco County). Supplement amounts are based on average rainfall โ€” 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" 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.

Celery needs ~1,600 GDD — county provides 2,272 GDD Excellent fit

Celery Planting Timeline โ€” Iosco County, MI

Celery Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 โ€“ Apr 23
Transplant Outdoors May 14 May 14 โ€“ May 28
Direct Sow April 30 Apr 30 โ€“ May 21
Harvest August 6 Aug 6 โ€“ Oct 1
Fall Sowing July 25 Jul 25 โ€“ Aug 8

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.3"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

142 days in Iosco County

Growing Tips for Celery in Iosco County

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

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 Iosco County, MI?

Iosco County is in Zone 5a with an average last frost of May 14. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Iosco County, MI?

Iosco County, Michigan is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is October 3.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Iosco County gardeners in Zone 5a 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 Iosco County, MI. Local conditions may vary. Last updated: April 2026.