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When to Plant Celery in DeWitt County, IL

DeWitt County, Illinois Zone 6a May

Top priorities for DeWitt County, Illinois gardeners in May

Here's what deserves your attention in DeWitt County, Illinois this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 15
Avg. first frost October 17
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Start celery indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

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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.

DeWitt County, Illinois is in USDA Zone 6a. The average last spring frost is April 15 and the first fall frost is October 17, giving you a growing season of approximately 185 days.

At an elevation of 801 feet, DeWitt County receives approximately 31.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Celery to ensure they mature before fall.

DeWitt County, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 15
185 growing days
First Fall Frost October 17

DeWitt County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Start indoors: Mar 6 Transplant: Apr 10 🍅 Harvest: Jul 3 – Aug 28
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 8 – Sep 2
Safe Start (90%) ✓ Fits season (47 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.

Soil Compatibility in DeWitt County

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

Soil pH

Your soil pH (6.1–7.0) is within Celery's preferred range (6.0–7.0).

Soil Texture

The silt loam soil in DeWitt County is excellent for Celery — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Celery is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is excellent (5.0%) — 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 185-day season

Sow every 9.1 weeks. Last sowing by Jun 19 to harvest before frost.

For a dedicated fall crop, sow by Aug 08.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.7″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 1,594 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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 5.6" 2.6" 3" 🚿 Regular watering
May 5.6" 4.1" 1.5" 💧 Light watering
Jun 5.6" 4.3" 1.3" 💧 Light watering
Jul 5.6" 3.2" 2.4" 💧 Light watering
Aug 5.6" 3.6" 2" 💧 Light watering
Sep 5.6" 2.7" 2.9" 🚿 Regular watering
Oct 5.6" 2.3" 3.3" 🚿 Regular watering
Nov 2.1" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in DeWitt County). Supplement amounts are based on average rainfall — 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" — every day above 50°F 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 ~1,300 GDD — county provides 2,405 GDD Excellent fit

Celery Planting Timeline — DeWitt County, IL

Celery Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 15 Apr 15 – Apr 29
Direct Sow April 1 Apr 1 – Apr 22
Harvest July 8 Jul 8 – Sep 2
Fall Sowing August 8 Aug 8 – Aug 22

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 2-3 times/week

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

185 days in DeWitt County

Growing Tips for Celery in DeWitt County

Direct sow Celery outdoors after April 15 in DeWitt 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 DeWitt County, IL?

DeWitt County is in Zone 6a with an average last frost of April 15. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is DeWitt County, IL?

DeWitt County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 15 and first fall frost is October 17.

🌱

Your DeWitt County Garden Planner — Free

A 24-page printable planner built for DeWitt County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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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 DeWitt County, IL. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.