When to Plant Carrots in Larimer 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.
Larimer County, Colorado is in USDA Zone 5a. 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 Soil Profile
Soil Type
Loam
Soil pH
6.4-8.2
Drainage
Well Drained
Plant Planting Risk Windows
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
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Carrots
Sow every 6.9 weeks. Last sowing by Jul 18 to harvest before frost.
For a dedicated fall crop, sow by Jul 28.
Plant Water Budget
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 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
| Month | Activities |
|---|---|
| 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 5a
📆 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
Check more plant combinations with our Companion Planting Checker →
Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.
Carrots in Other Locations
Frequently Asked Questions
When should I plant Carrots in Larimer County, CO?
Larimer County is in Zone 5a 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 5a. The average last spring frost is May 2 and first fall frost is October 6.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Larimer County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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