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When to plant Celeriac in Clay County, MN

Plant Celeriac in Clay County, when soil hits 50°F — usually May 4. Continue planting through May 25 for the spring crop. A second sowing from July 8 to July 22 extends the harvest into fall.

When to Plant Celeriac in Clay County, MN

Clay County, Minnesota Zone 4a June

What to do in June

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

Avg. last frost May 11
Avg. first frost September 30
Soil temp (4") 59°F
Watering Low
Pest pressure Moderate
Daylight 15.7 hrs
  1. Sow celeriac in trays indoors

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

Looking ahead to July
  • Fall sowing: 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.

Clay County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 30, giving you a growing season of approximately 142 days.

At an elevation of 1,220 feet, Clay County receives approximately 35.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Celeriac to ensure they mature before fall.

Clay County, MN (Zone 4a) Short season
142 days
Last Spring Frost May 11
142 growing days
First Fall Frost September 30

Clay County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.9

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Start indoors: Mar 21 Transplant: May 2 🍅 Harvest: Aug 15 – Sep 19
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 30 Transplant: May 11 🍅 Harvest: Aug 24 – Sep 28
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Apr 11 Transplant: May 23 🍅 Harvest: Sep 5 – Oct 10

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 Clay County

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

Soil pH

Your soil pH (5.9–6.9) overlaps with Celeriac's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — 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
1.0″/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 1.4" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 3.9" 0" ❄️ Dormant
May 3.9" 3.8" 0.1" 💧 Light watering
Jun 3.9" 3.8" 0.1" 💧 Light watering
Jul 3.9" 4.3" 0" ✅ Rainfall sufficient
Aug 3.9" 4.2" 0" ✅ Rainfall sufficient
Sep 3.9" 2.8" 1.1" 💧 Light watering
Oct 2.6" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Clay 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 ~1,100 GDD — county provides 1,420 GDD Good fit

Celeriac Planting Timeline — Clay County, MN

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 – Apr 13
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 4 May 4 – May 25
Harvest August 24 Aug 24 – Sep 28
Fall Sowing July 8 Jul 8 – Jul 22

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
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 4a

📆 Growing Season

142 days in Clay County

Growing Tips for Celeriac in Clay County

Direct sow Celeriac outdoors after May 11 in Clay 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 Clay County, MN?

Clay County is in Zone 4a with an average last frost of May 11. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clay County, MN?

Clay County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 30.

When should I plant Celeriac in Clay County, MN?

In Clay County, MN, plant Celeriac after the last frost (around May 11) and before the first frost (around September 30). Best results when soil holds above 50°F.

What growing zone is Clay County, MN for Celeriac?

Clay County sits in USDA Zone 4a. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Clay County's climate?

Yes — Celeriac grows well in Clay County's temperate climate. Clay County averages a 142-day frost-free season, with last frost around May 11 and first frost around September 30.

🌱

Your Clay County Garden Planner — Free

A 22-page printable planner built for Clay County (Zone 4a). 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 Clay County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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