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When to Plant Celery in Winnebago 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.

Winnebago County, Iowa is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.

At an elevation of 520 feet, Winnebago County receives approximately 32.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Celery to ensure they mature before fall.

Winnebago County, IA (Zone 4b) Moderate season
161 days
Last Spring Frost April 28
161 growing days
First Fall Frost October 6

Winnebago County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (23 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🍅 Harvest: Jul 15 – Sep 9
Recommended (50%) ✓ Fits season (21 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Jul 21 – Sep 15
Safe Start (90%) ✓ Fits season (19 days to spare)
Start indoors: Mar 29 Transplant: May 10 🍅 Harvest: Aug 2 – Sep 27

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
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 942 gal / 100 sq ft
Celery needs ~1,300 GDD — county provides 2,093 GDD Excellent fit

Celery Planting Timeline โ€” Winnebago County, IA

Celery Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 โ€“ Mar 31
Transplant Outdoors April 28 Apr 28 โ€“ May 12
Direct Sow April 21 Apr 21 โ€“ May 12
Fall Sowing July 14 Jul 14 โ€“ Jul 28
Harvest July 21 Jul 21 โ€“ Sep 15

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

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June โ€”
July Fall Sowing Harvest
August 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 4b

Growing Season

161 days

Growing Tips for Winnebago 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

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Frequently Asked Questions

When should I plant Celery in Winnebago County, IA?

Winnebago County is in Zone 4b with an average last frost of April 28. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Winnebago County, IA?

Winnebago County, Iowa is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 6.

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Plan Your Garden with Confidence

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