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When to Plant Carrots in Niobrara County, WY

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.

Niobrara County, Wyoming is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 21, giving you a growing season of approximately 129 days.

At an elevation of 5,262 feet, Niobrara County receives approximately 19.5 inches of rainfall annually with predominantly loam soil. Summer highs average 82ยฐF, 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.

Niobrara County, WY (Zone 4b) Short season
129 days
Last Spring Frost May 15
129 growing days
First Fall Frost September 21

Niobrara County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Transplant: May 13 🍅 Harvest: Jul 15 – Aug 19
Recommended (50%) ✓ Fits season (31 days to spare)
Transplant: May 15 🍅 Harvest: Jul 17 – Aug 21
Safe Start (90%) ✓ Fits season (26 days to spare)
Transplant: Jun 4 🍅 Harvest: Aug 6 – Sep 10

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
0.4″/week
Watering frequency 1-2 times/week
Season total 503 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Carrots needs ~805 GDD — county provides 1,483 GDD Excellent fit

Carrots Planting Timeline โ€” Niobrara County, WY

Carrots Planting Calendar

Activity When Date Range
Direct Sow May 8 May 8 โ€“ May 29
Fall Sowing June 29 Jun 29 โ€“ Jul 13
Harvest July 10 Jul 10 โ€“ Aug 14

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 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

129 days

Growing Tips for Niobrara 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 Niobrara County, WY?

Niobrara County is in Zone 4b with an average last frost of May 15. Plan your Carrots planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Niobrara County, WY?

Niobrara County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 21.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Niobrara County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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 Niobrara County, WY. Local conditions may vary. Last updated: April 2026.