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When to plant Celeriac in Castleton,

Plant Celeriac in Castleton from April 7 to April 28 in spring. Castleton sits in USDA Zone 5b, with last frost around April 21 and first frost on October 12. A second sowing from August 3 to August 17 extends the harvest into fall.

When to Plant Celeriac in Castleton, IL

Castleton, IL Zone 5b June

June in the garden — Castleton, IL

We've pulled the most time-sensitive tasks for Castleton, IL this June and put them front and centre. Tackle them in order.

Avg. last frost April 21
Avg. first frost October 12
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.

Castleton, Illinois is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 12, giving you a growing season of approximately 174 days.

At an elevation of 1,071 feet, Stark County receives approximately 33.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Celeriac to ensure they mature before fall.

Castleton, IL (Zone 5b) Moderate season
174 days
Last Spring Frost April 21
174 growing days
First Fall Frost October 12
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Castleton Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.9

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (35 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🍅 Harvest: Jul 30 – Sep 3
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Aug 4 – Sep 8
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Apr 3 Transplant: May 8 🍅 Harvest: Aug 21 – Sep 25

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 Castleton

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.8%) — 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
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 134 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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.9" 3.5" 0.4" 💧 Light watering
May 3.9" 4.1" 0" ✅ Rainfall sufficient
Jun 3.9" 4.1" 0" ✅ Rainfall sufficient
Jul 3.9" 3.5" 0.4" 💧 Light watering
Aug 3.9" 3.3" 0.6" 💧 Light watering
Sep 3.9" 2.8" 1.1" 💧 Light watering
Oct 3.9" 2.9" 1" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 1.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Stark 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 ~1,430 GDD — county provides 2,262 GDD Excellent fit

Celeriac Planting Timeline — Castleton, IL

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 7 Apr 7 – Apr 28
Harvest August 4 Aug 4 – Sep 8
Fall Sowing August 3 Aug 3 – Aug 17

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 5b

📆 Growing Season

174 days in Stark County

Growing Tips for Celeriac in Castleton

Direct sow Celeriac outdoors after April 21 in Stark 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 Castleton, ?

In Castleton, , plant Celeriac after the last frost (around April 21) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Castleton, for Celeriac?

Castleton sits in USDA Zone 5b. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Castleton's climate?

Yes — Celeriac grows well in Castleton's temperate climate. Castleton averages a 174-day frost-free season, with last frost around April 21 and first frost around October 12.

🌱

Your Stark County Garden Planner — Free

A 22-page printable planner built for Stark County (Zone 5b). 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 Stark County, IL. Local conditions may vary. Last updated: June 2026.