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When to plant Celeriac in Saint Libory, IL

Plant Celeriac in Saint Libory after April 2; the prime window is March 19–April 9. A second sowing from August 24 to September 7 extends the harvest into fall.

When to Plant Celeriac in Saint Libory, IL

St. Clair County, Illinois Zone 7a July

July in St. Clair County, Illinois — your action list

Welcome to July in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 2
Avg. first frost November 2
Soil temp (4") 81°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Start harvesting celeriac

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong August, finish these tasks
  • First harvests: celeriac
  • Fall sowing: celeriac

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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.

Saint Libory, Illinois is in USDA Zone 7a. The average last spring frost is April 2 and the first fall frost is November 2, giving you a growing season of approximately 214 days.

At an elevation of 711 feet, St. Clair County receives approximately 34.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Celeriac during the growing season.

Saint Libory, IL (Zone 7a) Long season
214 days
Last Spring Frost April 2
214 growing days
First Fall Frost November 2

Saint Libory Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.3

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (76 days to spare)
Start indoors: Feb 19 Transplant: Mar 26 🍅 Harvest: Jul 9 – Aug 13
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Feb 26 Transplant: Apr 2 🍅 Harvest: Jul 16 – Aug 20
Safe Start (90%) ✓ Fits season (80 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🍅 Harvest: Jul 31 – Sep 4

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 Saint Libory

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

Soil pH

Your soil pH (6.0–7.3) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in St. Clair 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
0.3″/week
Watering frequency Only during dry spells
Season total 527 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.5" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3.9" 3.2" 0.7" 💧 Light watering
May 3.9" 3.8" 0.1" 💧 Light watering
Jun 3.9" 4" 0" ✅ Rainfall sufficient
Jul 3.9" 3.8" 0.1" 💧 Light watering
Aug 3.9" 3.9" 0" ✅ Rainfall sufficient
Sep 3.9" 3.3" 0.6" 💧 Light watering
Oct 3.9" 2.5" 1.4" 💧 Light watering
Nov 3.9" 2.4" 1.5" 💧 Light watering
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in St. Clair 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 ~1,842 GDD — county provides 3,584 GDD Excellent fit

Celeriac Planting Timeline — Saint Libory, IL

Celeriac Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors April 2 Apr 2 – Apr 16
Direct Sow March 19 Mar 19 – Apr 9
Harvest July 16 Jul 16 – Aug 20
Fall Sowing August 24 Aug 24 – Sep 7

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

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

214 days in St. Clair County

Growing Tips for Celeriac in Saint Libory

Direct sow Celeriac outdoors after April 02 in St. Clair 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 Saint Libory, IL?

In Saint Libory, IL, plant Celeriac after the last frost (around April 2) and before the first frost (around November 2). Best results when soil holds above 50°F.

What growing zone is Saint Libory, IL for Celeriac?

Saint Libory sits in USDA Zone 7a. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Saint Libory's climate?

Yes — Celeriac grows well in Saint Libory's temperate climate. Saint Libory averages a 214-day frost-free season, with last frost around April 2 and first frost around November 2.

🌱

Your St. Clair County Garden Planner — Free

A 22-page printable planner built for St. Clair County (Zone 7a). 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 St. Clair County, IL. Local conditions may vary. Last updated: July 2026.