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When to Plant Celery in Warren County, IL

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.

Warren County, Illinois is in USDA Zone 5a. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 801 feet, Warren County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87ยฐF, providing good warmth for Celery during the growing season.

Warren County, IL (Zone 5a) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Warren County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: Jun 30 – Aug 25
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Mar 9 Transplant: Apr 13 🍅 Harvest: Jul 6 – Aug 31
Safe Start (90%) ✓ Fits season (55 days to spare)
Start indoors: Mar 24 Transplant: Apr 28 🍅 Harvest: Jul 21 – Sep 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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,441 gal / 100 sq ft
Drought risk

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

Celery needs ~1,525 GDD — county provides 2,912 GDD Excellent fit

Celery Planting Timeline โ€” Warren County, IL

Celery Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 โ€“ Mar 23
Transplant Outdoors April 13 Apr 13 โ€“ Apr 27
Direct Sow March 30 Mar 30 โ€“ Apr 20
Fall Sowing August 12 Aug 12 โ€“ Aug 26
Harvest July 6 Jul 6 โ€“ Aug 31

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

Month-by-Month Timeline

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

191 days

Growing Tips for Warren 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 Warren County, IL?

Warren County is in Zone 5a with an average last frost of April 13. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Warren County, IL?

Warren County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 13 and first fall frost is October 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Warren 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 Warren County, IL. Local conditions may vary. Last updated: April 2026.