Blog

When to Plant Celeriac in Forest County, WI

Forest County, Wisconsin Zone 4b May

Your May game plan for Forest County, Wisconsin

Your Forest County, Wisconsin garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 20
Avg. first frost September 30
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Harden off and plant celeriac

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

  2. Plant celeriac from seed, right in the garden

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

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.

Forest County, Wisconsin is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 30, giving you a growing season of approximately 133 days.

At an elevation of 556 feet, Forest County receives approximately 34.2 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.

Forest County, WI (Zone 4b) Short season
133 days
Last Spring Frost May 20
133 growing days
First Fall Frost September 30

Forest County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 3 Transplant: May 15 🍅 Harvest: Aug 28 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Apr 8 Transplant: May 20 🍅 Harvest: Sep 2 – Oct 7
Safe Start (90%) ✗ May not fit
Start indoors: Apr 19 Transplant: May 31 🍅 Harvest: Sep 13 – Oct 18

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 Forest County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
1.1″/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 1.2" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 3.9" 4" 0" ✅ Rainfall sufficient
Jun 3.9" 4.1" 0" ✅ Rainfall sufficient
Jul 3.9" 3.6" 0.3" 💧 Light watering
Aug 3.9" 4.1" 0" ✅ Rainfall sufficient
Sep 3.9" 3.4" 0.5" 💧 Light watering
Oct 2.5" 0" ❄️ Dormant
Nov 2.4" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Forest 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 ~1,348 GDD — county provides 1,629 GDD Good fit

Celeriac Planting Timeline — Forest County, WI

Celeriac Planting Calendar

Activity When Date Range
Start Indoors April 8 Apr 8 – Apr 22
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest September 2 Sep 2 – Oct 7
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Fall Sowing
August
September Harvest
October Harvest
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

133 days in Forest County

Growing Tips for Celeriac in Forest County

Direct sow Celeriac outdoors after May 20 in Forest County when soil has warmed and frost danger has passed.

Your 133.0-day growing season in Forest County is tight for Celeriac (100.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Forest County, WI?

Forest County is in Zone 4b with an average last frost of May 20. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Forest County, WI?

Forest County, Wisconsin is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 30.

🌱

Your Forest County Garden Planner — Free

A 24-page printable planner built for Forest 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.

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 Forest County, WI. 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.