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When to Plant Celery in Marshall County, IA

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.

Marshall County, Iowa is in USDA Zone 5a. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 1,379 feet, Marshall County receives approximately 33.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Celery to ensure they mature before fall.

Marshall County, IA (Zone 5a) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Marshall County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (22 days to spare)
Start indoors: Mar 19 Transplant: Apr 23 🍅 Harvest: Jul 16 – Sep 10
Recommended (50%) ✓ Fits season (18 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Jul 25 – Sep 19
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Aug 5 – Sep 30

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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,046 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Celery needs ~1,225 GDD — county provides 1,935 GDD Excellent fit

Celery Planting Timeline โ€” Marshall County, IA

Celery Planting Calendar

Activity When Date Range
Start Indoors March 28 Mar 28 โ€“ Apr 11
Transplant Outdoors May 2 May 2 โ€“ May 16
Direct Sow April 18 Apr 18 โ€“ May 9
Fall Sowing July 29 Jul 29 โ€“ Aug 12
Harvest July 25 Jul 25 โ€“ Sep 19

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 Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing Harvest
August Fall Sowing Harvest
September Harvest
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5a

Growing Season

158 days

Growing Tips for Marshall County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Celery in Marshall County, IA?

Marshall County is in Zone 5a with an average last frost of May 2. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Marshall County, IA?

Marshall County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is May 2 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Marshall County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Marshall County, IA. Local conditions may vary. Last updated: April 2026.