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When to Plant Celeriac in Pierce County, WI

Pierce County, Wisconsin Zone 4b August

August to-do list for Pierce County, Wisconsin

Welcome to August in Zone 4b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 28
Avg. first frost October 8
Soil temp (4") 74°F
Watering Moderate
Pest pressure High
Daylight 13.9 hrs
  1. Harvest celeriac as they ripen

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Looking ahead to September
  • 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.

Pierce County, Wisconsin is in USDA Zone 4b. The average last spring frost is April 28 and the first fall frost is October 8, giving you a growing season of approximately 163 days.

At an elevation of 523 feet, Pierce County receives approximately 35.1 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.

Pierce County, WI (Zone 4b) Moderate season
163 days
Last Spring Frost April 28
163 growing days
First Fall Frost October 8

Pierce County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.8

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (26 days to spare)
Start indoors: Mar 8 Transplant: Apr 19 🍅 Harvest: Aug 2 – Sep 6
Recommended (50%) ✓ Fits season (23 days to spare)
Start indoors: Mar 17 Transplant: Apr 28 🍅 Harvest: Aug 11 – Sep 15
Safe Start (90%) ✓ Fits season (22 days to spare)
Start indoors: Apr 4 Transplant: May 16 🍅 Harvest: Aug 29 – Oct 3

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 Pierce County

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

Soil pH

Your soil pH (5.9–6.8) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Celeriac will thrive.

How to Plant Celeriac

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Celeriac Water Budget

Plant needs
0.9″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 3.9" 3.7" 0.2" 💧 Light watering
May 3.9" 4.2" 0" ✅ Rainfall sufficient
Jun 3.9" 4.5" 0" ✅ Rainfall sufficient
Jul 3.9" 3.6" 0.3" 💧 Light watering
Aug 3.9" 3.6" 0.3" 💧 Light watering
Sep 3.9" 3.3" 0.6" 💧 Light watering
Oct 3.9" 2.7" 1.2" 💧 Light watering
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Pierce 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 2,119 GDD Excellent fit

Celeriac Planting Timeline — Pierce County, WI

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 28 Apr 28 – May 12
Direct Sow April 21 Apr 21 – May 12
Harvest August 11 Aug 11 – Sep 15
Fall Sowing July 16 Jul 16 – Jul 30

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 Direct Sow
June
July Fall Sowing
August 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: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

163 days in Pierce County

Growing Tips for Celeriac in Pierce County

Direct sow Celeriac outdoors after April 28 in Pierce 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 Pierce County, WI?

Pierce County is in Zone 4b with an average last frost of April 28. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pierce County, WI?

Pierce County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is April 28 and first fall frost is October 8.

🌱

Your Pierce County Garden Planner — Free

A 22-page printable planner built for Pierce County (Zone 4b). 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 Pierce County, WI. Local conditions may vary. Last updated: August 2026.

Sources & credits

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