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When to plant Celeriac in Sidell, IL

In Zone 6a (Sidell), direct-sow Celeriac between March 31 and April 21 for spring, after the April 14 last-frost mark. A second sowing from August 7 to August 21 extends the harvest into fall.

When to Plant Celeriac in Sidell, IL

Vermilion County, Illinois Zone 6a June

June to-do list for Vermilion County, Illinois

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

Avg. last frost April 14
Avg. first frost October 16
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
To set up a strong July, finish these tasks
  • First harvests: 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.

Sidell, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 16, giving you a growing season of approximately 185 days.

At an elevation of 1,218 feet, Vermilion County receives approximately 31.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Celeriac during the growing season.

Sidell, IL (Zone 6a) Moderate season
185 days
Last Spring Frost April 14
185 growing days
First Fall Frost October 16

Sidell Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.9

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (43 days to spare)
Start indoors: Mar 7 Transplant: Apr 11 🍅 Harvest: Jul 25 – Aug 29
Recommended (50%) ✓ Fits season (45 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Jul 28 – Sep 1
Safe Start (90%) ✓ Fits season (40 days to spare)
Start indoors: Mar 29 Transplant: May 3 🍅 Harvest: Aug 16 – Sep 20

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 Sidell

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

Soil pH

Your soil pH (6.2–6.9) is within Celeriac's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — 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 379 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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 3.9" 3.1" 0.8" 💧 Light watering
May 3.9" 3.9" 0" ✅ Rainfall sufficient
Jun 3.9" 3.7" 0.2" 💧 Light watering
Jul 3.9" 3.8" 0.1" 💧 Light watering
Aug 3.9" 3.5" 0.4" 💧 Light watering
Sep 3.9" 2.5" 1.4" 💧 Light watering
Oct 3.9" 2.1" 1.8" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Vermilion 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 ~1,512 GDD — county provides 2,543 GDD Excellent fit

Celeriac Planting Timeline — Sidell, IL

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 – Mar 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow March 31 Mar 31 – Apr 21
Harvest July 28 Jul 28 – Sep 1
Fall Sowing August 7 Aug 7 – Aug 21

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors Direct Sow
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

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

185 days in Vermilion County

Growing Tips for Celeriac in Sidell

Direct sow Celeriac outdoors after April 14 in Vermilion 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 Sidell, IL?

In Sidell, IL, plant Celeriac after the last frost (around April 14) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Sidell, IL for Celeriac?

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

Can Celeriac grow in Sidell's climate?

Yes — Celeriac grows well in Sidell's temperate climate. Sidell averages a 185-day frost-free season, with last frost around April 14 and first frost around October 16.

🌱

Your Vermilion County Garden Planner — Free

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