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When to Plant Fennel (herb) in Kit Carson County, CO

Kit Carson County, Colorado Zone 6a April

Your April planting checklist for Kit Carson County, Colorado

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Kit Carson County, Colorado.

Avg. last frost May 9
Avg. first frost October 8
Soil temp (4") 27°F
Watering High
Pest pressure Low
Daylight 13 hrs
  1. Put fennel (herb) seeds straight in the ground

    Your soil is 27°F — warm enough for these to germinate without babying.

May will be here before you know it — start on
  • Transplants going out: fennel (herb)

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Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.

Kit Carson County, Colorado is in USDA Zone 5a. The average last spring frost is May 9 and the first fall frost is October 8, giving you a growing season of approximately 152 days.

At an elevation of 6,382 feet, Kit Carson County receives approximately 23.2 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Fennel (herb) during the growing season.

Kit Carson County, CO (Zone 5a) Moderate season
152 days
Last Spring Frost May 9
152 growing days
First Fall Frost October 8
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Kit Carson County Soil Profile

Soil Type

Loam

Soil pH

6.4-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 27 Transplant: Apr 24 🍅 Harvest: Jun 26 – Sep 4
Recommended (50%) ✓ Fits season (26 days to spare)
Start indoors: Apr 4 Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12
Safe Start (90%) ✓ Fits season (30 days to spare)
Start indoors: Apr 15 Transplant: May 13 🍅 Harvest: Jul 15 – Sep 23

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 Kit Carson County

How your county's soil matches Fennel (herb)'s growing requirements.

Soil pH

Your soil pH (6.4–8.0) is more alkaline than Fennel (herb) prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Kit Carson County is excellent for Fennel (herb) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Fennel (herb)

1"
Planting Depth
15"
Between Plants
24"
Between Rows

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

Succession Planting Fennel (herb)

2
successive plantings in your 152-day season

Sow every 6.9 weeks. Last sowing by Jul 10 to harvest before frost.

For a dedicated fall crop, sow by Jul 30.

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 583 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Fennel (herb)

Fennel (herb) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Fennel (herb) Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2.2" 2.1" 💧 Light watering
Aug 4.3" 2.7" 1.6" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 1.5" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Fennel (herb) 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.

Fennel (herb) needs ~1,031 GDD — county provides 2,090 GDD Excellent fit

Fennel (herb) Planting Timeline — Kit Carson County, CO

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest July 4 Jul 4 – Sep 12
Fall Sowing July 30 Jul 30 – Aug 13

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June
July Fall Sowing Harvest
August Fall Sowing Harvest
September Harvest
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

152 days in Kit Carson County

Growing Tips for Fennel (herb) in Kit Carson County

Direct sow Fennel (herb) outdoors after May 09 in Kit Carson County when soil has warmed and frost danger has passed.

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

Kit Carson County receives only 23" of rain annually. Fennel (herb) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow in spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Kit Carson County, CO?

Kit Carson County is in Zone 5a with an average last frost of May 9. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kit Carson County, CO?

Kit Carson County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 9 and first fall frost is October 8.

🌱

Your Kit Carson County Garden Planner — Free

A 24-page printable planner built for Kit Carson County (Zone 5a). 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 Kit Carson County, CO. Local conditions may vary. Last updated: April 2026.

Sources & credits

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