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When to Plant Celeriac in Campbell County, WY

Campbell County, Wyoming Zone 5a May

Your May gardening checklist

A quick May briefing for Campbell County, Wyoming gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 20
Avg. first frost September 20
Soil temp (4") 30°F
Watering High
Pest pressure Low
Daylight 14.6 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

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

A few tasks this May that'll pay off in June
  • Starting indoors: 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.

Campbell County, Wyoming is in USDA Zone 5a. The average last spring frost is May 20 and the first fall frost is September 20, giving you a growing season of approximately 123 days.

At an elevation of 8,132 feet, Campbell County receives approximately 22.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Celeriac to ensure they mature before fall.

Campbell County, WY (Zone 5a) Short season
123 days
Last Spring Frost May 20
123 growing days
First Fall Frost September 20

Campbell County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Aug 27 – Oct 1
Recommended (50%) ✗ May not fit
Start indoors: Apr 15 Transplant: May 20 🍅 Harvest: Sep 2 – Oct 7
Safe Start (90%) ✗ May not fit
Start indoors: May 3 Transplant: Jun 7 🍅 Harvest: Sep 20 – Oct 25

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 Campbell County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Celeriac prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). 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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 182 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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 3.9" 2.7" 1.2" 💧 Light watering
Jun 3.9" 1.4" 2.5" 🚿 Regular watering
Jul 3.9" 2" 1.9" 💧 Light watering
Aug 3.9" 2.4" 1.5" 💧 Light watering
Sep 3.9" 1.6" 2.3" 🚿 Regular watering
Oct 2.2" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Campbell 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 1,506 GDD Good fit

Celeriac Planting Timeline — Campbell County, WY

Celeriac Planting Calendar

Activity When Date Range
Start Indoors April 15 Apr 15 – Apr 29
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 6 May 6 – May 27
Harvest September 2 Sep 2 – Oct 7
Fall Sowing July 12 Jul 12 – Jul 26

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
July Fall Sowing
August
September Harvest
October Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

123 days in Campbell County

Growing Tips for Celeriac in Campbell County

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

Your 123.0-day growing season in Campbell 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.

Campbell County receives only 22" of rain annually. Celeriac needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Campbell County, WY?

Campbell County is in Zone 5a 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 Campbell County, WY?

Campbell County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is May 20 and first fall frost is September 20.

🌱

Your Campbell County Garden Planner — Free

A 24-page printable planner built for Campbell County (Zone 5a). 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 Campbell County, WY. 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.