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When to Plant Celery in Phillips 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.

Phillips County, Colorado is in USDA Zone 5a. The average last spring frost is May 4 and the first fall frost is October 7, giving you a growing season of approximately 156 days.

At an elevation of 5,494 feet, Phillips County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87ยฐF, providing good warmth for Celery during the growing season.

Phillips County, CO (Zone 5a) Moderate season
156 days
Last Spring Frost May 4
156 growing days
First Fall Frost October 7

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jul 23 – Sep 17
Recommended (50%) ✓ Fits season (16 days to spare)
Start indoors: Mar 30 Transplant: May 4 🍅 Harvest: Jul 27 – Sep 21
Safe Start (90%) ✓ Fits season (11 days to spare)
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Aug 11 – Oct 6

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 Phillips County

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

Soil pH

Your soil pH (6.5โ€“7.8) is more alkaline than Celery prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Phillips County is excellent for Celery โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Celery is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Celery.

How to Plant Celery

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Celery

2
successive plantings in your 156-day season

Sow every 9.1 weeks. Last sowing by Jun 09 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.6″/week
You supply
1.4″/week
Watering frequency 2-3 times/week
Season total 1,869 gal / 100 sq ft
Drought risk

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

Celery needs ~1,525 GDD — county provides 2,379 GDD Excellent fit

Celery Planting Timeline โ€” Phillips County, CO

Celery Planting Calendar

Activity When Date Range
Start Indoors March 30 Mar 30 โ€“ Apr 13
Transplant Outdoors May 4 May 4 โ€“ May 18
Direct Sow April 20 Apr 20 โ€“ May 11
Fall Sowing July 29 Jul 29 โ€“ Aug 12
Harvest July 27 Jul 27 โ€“ Sep 21

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

1.3"/week ยท 2-3 times/week

๐Ÿ“… Days to Maturity

80โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

156 days in Phillips County

Growing Tips for Celery in Phillips County

Direct sow Celery outdoors after May 04 in Phillips County when soil has warmed and frost danger has passed.

Common pests for Celery in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

Phillips County receives only 21" of rain annually. Celery needs consistent moisture โ€” install drip irrigation or water deeply 2-3 times per week.

General growing tips

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 Phillips County, CO?

Phillips County is in Zone 5a with an average last frost of May 4. Plan your Celery planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Phillips County, CO?

Phillips County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 4 and first fall frost is October 7.

๐ŸŒฑ

Plan Your Garden with Confidence

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

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Phillips County, CO. Local conditions may vary. Last updated: April 2026.