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When to Plant Celery in Clinton 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.

Clinton County, Illinois is in USDA Zone 6a. The average last spring frost is April 10 and the first fall frost is October 19, giving you a growing season of approximately 192 days.

At an elevation of 1,142 feet, Clinton County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85ยฐF, providing good warmth for Celery during the growing season.

Clinton County, IL (Zone 6a) Moderate season
192 days
Last Spring Frost April 10
192 growing days
First Fall Frost October 19

Clinton County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (52 days to spare)
Start indoors: Feb 28 Transplant: Apr 4 🍅 Harvest: Jun 27 – Aug 22
Recommended (50%) ✓ Fits season (52 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jul 3 – Aug 28
Safe Start (90%) ✓ Fits season (54 days to spare)
Start indoors: Mar 15 Transplant: Apr 19 🍅 Harvest: Jul 12 – Sep 6

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 Clinton County

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) 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.

Succession Planting Celery

2
successive plantings in your 192-day season

Sow every 9.1 weeks. Last sowing by Jun 21 to harvest before frost.

For a dedicated fall crop, sow by Aug 10.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 957 gal / 100 sq ft
Drought risk

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

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€” 1.6" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.9" 0" โ„๏ธ Dormant
Apr 5.6" 3.5" 2.1" ๐Ÿ’ง Light watering
May 5.6" 4.3" 1.3" ๐Ÿ’ง Light watering
Jun 5.6" 4.9" 0.7" ๐Ÿ’ง Light watering
Jul 5.6" 4.3" 1.3" ๐Ÿ’ง Light watering
Aug 5.6" 3.9" 1.7" ๐Ÿ’ง Light watering
Sep 5.6" 3.4" 2.2" ๐Ÿ’ง Light watering
Oct 5.6" 3.2" 2.4" ๐Ÿ’ง Light watering
Nov โ€” 2.6" 0" โ„๏ธ Dormant
Dec โ€” 1.7" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Clinton 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 ~1,375 GDD — county provides 2,640 GDD Excellent fit

Celery Planting Timeline โ€” Clinton County, IL

Celery Planting Calendar

Activity When Date Range
Start Indoors March 6 Mar 6 โ€“ Mar 20
Transplant Outdoors April 10 Apr 10 โ€“ Apr 24
Direct Sow March 27 Mar 27 โ€“ Apr 17
Harvest July 3 Jul 3 โ€“ Aug 28
Fall Sowing August 10 Aug 10 โ€“ Aug 24

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

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.3"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

192 days in Clinton County

Growing Tips for Celery in Clinton County

Direct sow Celery outdoors after April 10 in Clinton 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 Clinton County, IL?

Clinton County is in Zone 6a with an average last frost of April 10. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clinton County, IL?

Clinton County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 10 and first fall frost is October 19.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clinton County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

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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 Clinton County, IL. Local conditions may vary. Last updated: April 2026.