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When to plant Celeriac in Fremont County, CO

In Fremont County, plant Celeriac in spring between May 9 and May 30, once soil temps hold above 50°F. Fremont County's last frost averages May 23, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between July 17 and July 31 — roughly 100–120 days before the first frost on September 25.

When to Plant Celeriac in Fremont County, CO

Fremont County, Colorado Zone 6a June

June to-do list for Fremont County, Colorado

Each item below is timed to Fremont County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 23
Avg. first frost September 25
Soil temp (4") 52°F
Watering High
Pest pressure High
Daylight 14.7 hrs
  1. Sow celeriac in trays indoors

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

To set up a strong July, finish these tasks
  • 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.

Fremont County, Colorado is in USDA Zone 6a. The average last spring frost is May 23 and the first fall frost is September 25, giving you a growing season of approximately 125 days.

At an elevation of 6,575 feet, Fremont County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Celeriac to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celeriac successfully. Mulch heavily to conserve soil moisture.

Fremont County, CO (Zone 6a) Short season
125 days
Last Spring Frost May 23
125 growing days
First Fall Frost September 25

Fremont County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Celeriac Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Aug 24 – Sep 28
Recommended (50%) ✗ May not fit
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Sep 5 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Sep 28 – Nov 2

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 Fremont County

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

Soil pH

Your soil pH (6.7–8.3) is more alkaline than Celeriac prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). 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.

Celeriac Water Budget

Plant needs
0.9″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 372 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.9" 2" 1.9" 💧 Light watering
Jun 3.9" 1.5" 2.4" 🚿 Regular watering
Jul 3.9" 1.4" 2.5" 🚿 Regular watering
Aug 3.9" 1.7" 2.2" 🚿 Regular watering
Sep 3.9" 1.5" 2.4" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Fremont 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 1,625 GDD Good fit

Celeriac Planting Timeline — Fremont County, CO

Celeriac Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 – May 2
Transplant Outdoors May 23 May 23 – Jun 6
Direct Sow May 9 May 9 – May 30
Harvest September 5 Sep 5 – Oct 10
Fall Sowing July 17 Jul 17 – Jul 31

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Start Indoors 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 · 1-2 times/week

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

125 days in Fremont County

Growing Tips for Celeriac in Fremont County

Direct sow Celeriac outdoors after May 23 in Fremont County when soil has warmed and frost danger has passed.

Your 125.0-day growing season in Fremont 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.

Fremont County receives only 18" 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 Fremont County, CO?

Fremont County is in Zone 6a with an average last frost of May 23. Plan your Celeriac planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fremont County, CO?

Fremont County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 23 and first fall frost is September 25.

When should I plant Celeriac in Fremont County, CO?

In Fremont County, CO, plant Celeriac after the last frost (around May 23) and before the first frost (around September 25). Best results when soil holds above 50°F.

What growing zone is Fremont County, CO for Celeriac?

Fremont County sits in USDA Zone 6a. Celeriac grows reliably in zones 3a through 9b, so it's a good fit here.

Can Celeriac grow in Fremont County's climate?

Yes — Celeriac grows well in Fremont County's temperate climate. Fremont County averages a 125-day frost-free season, with last frost around May 23 and first frost around September 25.

🌱

Your Fremont County Garden Planner — Free

A 22-page printable planner built for Fremont County (Zone 6a). 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 Fremont County, CO. Local conditions may vary. Last updated: June 2026.

Sources & credits

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