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When to plant Carrots in Larimer County, CO

Larimer County's spring Carrots window runs April 18 through May 9. time plantings around the expected last-frost window for best survival. A second sowing from July 28 to August 11 extends the harvest into fall.

When to Plant Carrots in Larimer County, CO

Carrots
Larimer County, Colorado Zone 5b August

This month in Larimer County, Colorado

August is a pivotal month for Larimer County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 2
Avg. first frost October 6
Soil temp (4") 56°F
Watering High
Pest pressure High
Daylight 13.6 hrs

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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.

Larimer County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.

At an elevation of 7,108 feet, Larimer County receives approximately 23.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Carrots to ensure they mature before fall.

Larimer County, CO (Zone 5b) Moderate season
157 days
Last Spring Frost May 2
157 growing days
First Fall Frost October 6

Larimer County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.2

Drainage

Well Drained

Carrots Planting Risk Windows

Early Start (70% safe) ✓ Fits season (58 days to spare)
Transplant: Apr 28 🍅 Harvest: Jun 30 – Aug 4
Recommended (50%) ✓ Fits season (59 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (54 days to spare)
Transplant: May 21 🍅 Harvest: Jul 23 – Aug 27

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 Larimer County

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

Soil pH

Your soil pH (6.4–8.2) is more alkaline than Carrots prefers (6.0–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Carrots.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Carrots.

How to Plant Carrots

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Succession Planting Carrots

3
successive plantings in your 157-day season

Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.

For a dedicated fall crop, sow by Jul 28.

Carrots Water Budget

Plant needs
0.8″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 694 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Carrots

Carrots needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Carrots Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 3.5" 2.5" 1" 💧 Light watering
Jun 3.5" 1.9" 1.6" 💧 Light watering
Jul 3.5" 2.3" 1.2" 💧 Light watering
Aug 3.5" 2.5" 1" 💧 Light watering
Sep 3.5" 2" 1.5" 💧 Light watering
Oct 3.5" 1.9" 1.6" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Larimer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Carrots 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.

Carrots needs ~910 GDD — county provides 2,041 GDD Excellent fit

Carrots Planting Timeline — Larimer County, CO

Carrots Planting Calendar

Activity When Date Range
Direct Sow April 18 Apr 18 – May 9
Harvest June 20 Jun 20 – Jul 25
Fall Sowing July 28 Jul 28 – Aug 11

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

157 days in Larimer County

Growing Tips for Carrots in Larimer County

Direct sow Carrots outdoors after May 02 in Larimer County when soil has warmed and frost danger has passed.

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

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

🌾 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 35°F, under 50% humidity.

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

Frequently Asked Questions

When should I plant Carrots in Larimer County, CO?

Larimer County is in Zone 5b with an average last frost of May 2. Plan your Carrots planting based on this frost date — see the calendar above for exact timing.

What planting zone is Larimer County, CO?

Larimer County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 6.

When should I plant Carrots in Larimer County, CO?

In Larimer County, CO, plant Carrots after the last frost (around May 2) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Larimer County, CO for Carrots?

Larimer County sits in USDA Zone 5b. Carrots grows reliably in zones 3a through 10b, so it's a good fit here.

Can Carrots grow in Larimer County's climate?

Yes — Carrots grows well in Larimer County's temperate climate. Larimer County averages a 157-day frost-free season, with last frost around May 2 and first frost around October 6.

🌱

Your Larimer County Garden Planner — Free

A 22-page printable planner built for Larimer County (Zone 5b). 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 Larimer County, CO. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.