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When to Plant Celery in Fremont County, CO

Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Fremont County, Colorado is in USDA Zone 5b. 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 84ยฐF, so choose short-season varieties of Celery to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Celery successfully. Mulch heavily to conserve soil moisture.

Fremont County, CO (Zone 5b) 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

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Aug 3 – Sep 28
Recommended (50%) ✗ May not fit
Start indoors: Apr 18 Transplant: May 23 🍅 Harvest: Aug 15 – Oct 10
Safe Start (90%) ✗ May not fit
Start indoors: May 11 Transplant: Jun 15 🍅 Harvest: Sep 7 – 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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.6″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 1,173 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Celery needs ~1,300 GDD — county provides 1,625 GDD Good fit

Celery Planting Timeline โ€” Fremont County, CO

Celery Planting Calendar

Activity When Date Range
Start Indoors April 18 Apr 18 โ€“ May 2
Transplant Outdoors May 23 May 23 โ€“ Jun 6
Direct Sow May 9 May 9 โ€“ May 30
Fall Sowing July 17 Jul 17 โ€“ Jul 31
Harvest August 15 Aug 15 โ€“ Oct 10

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

High โ€” keep soil consistently moist

Days to Maturity

80โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 5b

Growing Season

125 days

Growing Tips for Fremont County

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Level Up Your Garden

Frequently Asked Questions

When should I plant Celery in Fremont County, CO?

Fremont County is in Zone 5b with an average last frost of May 23. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Fremont County, CO?

Fremont County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 23 and first fall frost is September 25.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Fremont County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.

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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: April 2026.