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When to Plant Carrots in Rio Grande County, CO

Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

Rio Grande County, Colorado is in USDA Zone 4b. The average last spring frost is May 31 and the first fall frost is September 19, giving you a growing season of approximately 111 days.

At an elevation of 6,254 feet, Rio Grande County receives approximately 15.8 inches of rainfall annually with predominantly loam soil. Summer highs average 80ยฐF, so choose short-season varieties of Carrots to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Carrots successfully. Mulch heavily to conserve soil moisture.

Rio Grande County, CO (Zone 4b) Short season
111 days
Last Spring Frost May 31
111 growing days
First Fall Frost September 19

Rio Grande 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 (12 days to spare)
Transplant: May 26 🍅 Harvest: Jul 28 – Sep 1
Recommended (50%) ✓ Fits season (13 days to spare)
Transplant: May 31 🍅 Harvest: Aug 2 – Sep 6
Safe Start (90%) ✓ Fits season (10 days to spare)
Transplant: Jun 14 🍅 Harvest: Aug 16 – Sep 20

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
1.0″/week
Rainfall provides
0.6″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 832 gal / 100 sq ft
Drought risk

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

Carrots needs ~700 GDD — county provides 1,110 GDD Excellent fit

Carrots Planting Timeline โ€” Rio Grande County, CO

Carrots Planting Calendar

Activity When Date Range
Direct Sow May 24 May 24 โ€“ Jun 14
Fall Sowing June 27 Jun 27 โ€“ Jul 11
Harvest July 26 Jul 26 โ€“ Aug 30

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“80 days

Soil pH

6 โ€“ 6.8

USDA Zone

Zone 4b

Growing Season

111 days

Growing Tips for Rio Grande County

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Level Up Your Garden

๐ŸŒพ Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35ยฐF, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial โ€” requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Rio Grande County, CO?

Rio Grande County is in Zone 4b with an average last frost of May 31. Plan your Carrots planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rio Grande County, CO?

Rio Grande County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is May 31 and first fall frost is September 19.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rio Grande County gardeners in Zone 4b 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 Rio Grande County, CO. Local conditions may vary. Last updated: April 2026.