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When to Plant Carrots in Weld County, CO

Weld County, Colorado Zone 5b May

May to-do list for Weld County, Colorado

Here's what deserves your attention in Weld County, Colorado this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost May 2
Avg. first frost October 7
Soil temp (4") 39°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
Looking ahead to June
  • First harvests: carrots

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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.

Weld County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 6,992 feet, Weld County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Carrots during the growing season. With low rainfall, drip irrigation is essential for growing Carrots successfully. Mulch heavily to conserve soil moisture.

Weld County, CO (Zone 5b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7
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Weld County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (60 days to spare)
Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 3
Recommended (50%) ✓ Fits season (60 days to spare)
Transplant: May 2 🍅 Harvest: Jul 4 – Aug 8
Safe Start (90%) ✓ Fits season (55 days to spare)
Transplant: May 19 🍅 Harvest: Jul 21 – Aug 25

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 Weld County

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

Soil pH

Your soil pH (6.6–8.1) is more alkaline than Carrots prefers (6.0–6.8). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). 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 158-day season

Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Jul 29.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.5″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 507 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 3.5" 2.3" 1.2" 💧 Light watering
Jun 3.5" 1.4" 2.1" 🚿 Regular watering
Jul 3.5" 1.7" 1.8" 🚿 Regular watering
Aug 3.5" 1.8" 1.7" 💧 Light watering
Sep 3.5" 1.7" 1.8" 🚿 Regular watering
Oct 3.5" 1.7" 1.8" 🚿 Regular watering
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Weld 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 ~1,068 GDD — county provides 2,409 GDD Excellent fit

Carrots Planting Timeline — Weld 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 29 Jul 29 – Aug 12

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
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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

158 days in Weld County

Growing Tips for Carrots in Weld County

Direct sow Carrots outdoors after May 02 in Weld 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 Weld County, CO?

Weld 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 Weld County, CO?

Weld County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.

🌱

Your Weld County Garden Planner — Free

A 24-page printable planner built for Weld 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 Weld County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

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