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When to plant Celeriac in Mc Lean,

For Mc Lean, gardeners: plant Celeriac April 4 through April 25 once soil reads 50°F. A second sowing from August 9 to August 23 extends the harvest into fall.

When to Plant Celeriac in Mc Lean, IL

Mc Lean, IL Zone 6a June

June in the garden — Mc Lean, IL

June is a pivotal month for Mc Lean, IL gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 18
Avg. first frost October 18
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 14.9 hrs

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Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.

Mc Lean, Illinois is in USDA Zone 6a. The average last spring frost is April 18 and the first fall frost is October 18, giving you a growing season of approximately 183 days.

At an elevation of 1,024 feet, McLean County receives approximately 31.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Celeriac during the growing season.

Mc Lean, IL (Zone 6a) Moderate season
183 days
Last Spring Frost April 18
183 growing days
First Fall Frost October 18
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Mc Lean Soil Profile

Soil Type

Silt Loam

Soil pH

6-7

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (40 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jul 28 – Sep 1
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Mar 14 Transplant: Apr 18 🍅 Harvest: Aug 1 – Sep 5
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 28 Transplant: May 2 🍅 Harvest: Aug 15 – Sep 19

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 Mc Lean

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Celeriac will thrive.

How to Plant Celeriac

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Celeriac Water Budget

Plant needs
0.9″/week
Rainfall provides
0.7″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 273 gal / 100 sq ft

Monthly Watering Guide for Celeriac

Celeriac needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Celeriac Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.9" 2.9" 1" 💧 Light watering
May 3.9" 4" 0" ✅ Rainfall sufficient
Jun 3.9" 3.8" 0.1" 💧 Light watering
Jul 3.9" 3.5" 0.4" 💧 Light watering
Aug 3.9" 3.2" 0.7" 💧 Light watering
Sep 3.9" 2.7" 1.2" 💧 Light watering
Oct 3.9" 2.8" 1.1" 💧 Light watering
Nov 2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in McLean County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Celeriac 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.

Celeriac needs ~1,595 GDD — county provides 2,653 GDD Excellent fit

Celeriac Planting Timeline — Mc Lean, IL

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 – Mar 28
Transplant Outdoors April 18 Apr 18 – May 2
Direct Sow April 4 Apr 4 – Apr 25
Harvest August 1 Aug 1 – Sep 5
Fall Sowing August 9 Aug 9 – Aug 23

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Only during dry spells

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

183 days in McLean County

Growing Tips for Celeriac in Mc Lean

Direct sow Celeriac outdoors after April 18 in McLean County when soil has warmed and frost danger has passed.

Common pests for Celeriac 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. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

When should I plant Celeriac in Mc Lean, ?

In Mc Lean, , plant Celeriac after the last frost (around April 18) and before the first frost (around October 18). Best results when soil holds above 50°F.

What growing zone is Mc Lean, for Celeriac?

Mc Lean sits in USDA Zone 6a. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Mc Lean's climate?

Yes — Celeriac grows well in Mc Lean's temperate climate. Mc Lean averages a 183-day frost-free season, with last frost around April 18 and first frost around October 18.

🌱

Your McLean County Garden Planner — Free

A 22-page printable planner built for McLean 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 McLean County, IL. Local conditions may vary. Last updated: June 2026.