Blog

When to Plant Celeriac in Lucas County, IA

Lucas County, Iowa Zone 5b May

Lucas County, Iowa gardeners: here's your May plan

Your garden in Lucas County, Iowa is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 21
Avg. first frost October 13
Soil temp (4") 60°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Start celeriac under lights

    You're about 22 weeks out from your last frost — the perfect window to get these germinating indoors.

Instant PDF download. No spam, unsubscribe any time.

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.

Lucas County, Iowa is in USDA Zone 5b. The average last spring frost is April 21 and the first fall frost is October 13, giving you a growing season of approximately 175 days.

At an elevation of 638 feet, Lucas County receives approximately 41.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Celeriac during the growing season.

Lucas County, IA (Zone 5b) Moderate season
175 days
Last Spring Frost April 21
175 growing days
First Fall Frost October 13

Lucas County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 29 – Sep 2
Recommended (50%) ✓ Fits season (35 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🍅 Harvest: Aug 4 – Sep 8
Safe Start (90%) ✓ Fits season (37 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Aug 17 – Sep 21

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 Lucas County

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

Soil pH

Your soil pH (6.3–6.9) is within Celeriac's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Celeriac.

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.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.9" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 3" 0" ❄️ Dormant
Apr 3.9" 3.7" 0.2" 💧 Light watering
May 3.9" 5.2" 0" ✅ Rainfall sufficient
Jun 3.9" 5.3" 0" ✅ Rainfall sufficient
Jul 3.9" 5" 0" ✅ Rainfall sufficient
Aug 3.9" 4.6" 0" ✅ Rainfall sufficient
Sep 3.9" 3.5" 0.4" 💧 Light watering
Oct 3.9" 2.7" 1.2" 💧 Light watering
Nov 2.9" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lucas 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 ~1,678 GDD — county provides 2,668 GDD Excellent fit

Celeriac Planting Timeline — Lucas County, IA

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 4 Aug 4 – Aug 18

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Lucas County

Growing Tips for Celeriac in Lucas County

Direct sow Celeriac outdoors after April 21 in Lucas 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 →

Frequently Asked Questions

When should I plant Celeriac in Lucas County, IA?

Lucas County is in Zone 5b with an average last frost of April 21. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lucas County, IA?

Lucas County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 21 and first fall frost is October 13.

🌱

Your Lucas County Garden Planner — Free

A 24-page printable planner built for Lucas 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lucas County, IA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.