When to plant Celeriac in Preemption, IL
Preemption's spring Celeriac window runs April 3 through April 24. time plantings around the expected last-frost window for best survival. A second sowing from August 6 to August 20 extends the harvest into fall.
When to Plant Celeriac in Preemption, IL
Mercer County, Illinois gardeners: here's your July plan
Your Mercer County, Illinois garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.
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Basket week: celeriac
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
August prep starts now
- First harvests: celeriac
- Fall sowing: celeriac
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.
Preemption, Illinois is in USDA Zone 5b. The average last spring frost is April 17 and the first fall frost is October 15, giving you a growing season of approximately 181 days.
At an elevation of 777 feet, Mercer County receives approximately 37.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Celeriac to ensure they mature before fall.
Preemption Soil Profile
Soil Type
Silt Loam
Soil pH
6.3-6.7
Drainage
Well Drained
Celeriac Planting Risk Windows
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 Preemption
How your county's soil matches Celeriac's growing requirements.
Soil pH
Your soil pH (6.3–6.7) is within Celeriac's preferred range (6.0–7.0).
Soil Texture
The silt loam soil in Mercer County is excellent for Celeriac — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (4.0%). Annual compost additions will help Celeriac.
How to Plant Celeriac
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Celeriac Water Budget
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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 2.9" | 0" | ❄️ Dormant |
| Apr | 3.9" | 3.7" | 0.2" | 💧 Light watering |
| May | 3.9" | 4" | 0" | ✅ Rainfall sufficient |
| Jun | 3.9" | 4.6" | 0" | ✅ Rainfall sufficient |
| Jul | 3.9" | 3.7" | 0.2" | 💧 Light watering |
| Aug | 3.9" | 4" | 0" | ✅ Rainfall sufficient |
| Sep | 3.9" | 3.4" | 0.5" | 💧 Light watering |
| Oct | 3.9" | 2.5" | 1.4" | 💧 Light watering |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Mercer 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 Planting Timeline — Preemption, IL
Celeriac Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 13 | Mar 13 – Mar 27 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Direct Sow | April 3 | Apr 3 – Apr 24 |
| Harvest | July 31 | Jul 31 – Sep 4 |
| Fall Sowing | August 6 | Aug 6 – Aug 20 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| 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 5b
📆 Growing Season
181 days in Mercer County
Growing Tips for Celeriac in Preemption
Direct sow Celeriac outdoors after April 17 in Mercer 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
Check more plant combinations with our Companion Planting Checker →
Celeriac in Other Locations
When should I plant Celeriac in Preemption, IL?
In Preemption, IL, plant Celeriac after the last frost (around April 17) and before the first frost (around October 15). Best results when soil holds above 50°F.
What growing zone is Preemption, IL for Celeriac?
Preemption sits in USDA Zone 5b. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.
Can Celeriac grow in Preemption's climate?
Yes — Celeriac grows well in Preemption's temperate climate. Preemption averages a 181-day frost-free season, with last frost around April 17 and first frost around October 15.
Your Mercer County Garden Planner — Free
A 22-page printable planner built for Mercer 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.