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When to Plant Fennel (herb) in Garfield County, UT

Garfield County, Utah Zone 6a May

May in the garden — Garfield County, Utah

We've pulled the most time-sensitive tasks for Garfield County, Utah this May and put them front and centre. Tackle them in order.

Avg. last frost May 27
Avg. first frost September 21
Soil temp (4") 45°F
Watering High
Pest pressure Low
Daylight 14 hrs
  1. Get fennel (herb) in the ground

    Frost risk is low now in Garfield County, Utah. If you've been covering beds overnight, you can stop.

  2. Direct-sow fennel (herb)

    Thin ruthlessly once seedlings are up. Crowded roots mean smaller crops from every plant.

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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.

Garfield County, Utah is in USDA Zone 6a. The average last spring frost is May 27 and the first fall frost is September 21, giving you a growing season of approximately 117 days.

At an elevation of 5,058 feet, Garfield County receives approximately 20.3 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Fennel (herb) to ensure they mature before fall.

Garfield County, UT (Zone 6a) Short season
117 days
Last Spring Frost May 27
117 growing days
First Fall Frost September 21

Garfield County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 10 Transplant: May 8 🍅 Harvest: Jul 10 – Sep 18
Recommended (50%) ✗ May not fit
Start indoors: Apr 22 Transplant: May 20 🍅 Harvest: Jul 22 – Sep 30
Safe Start (90%) ✗ May not fit
Start indoors: May 20 Transplant: Jun 17 🍅 Harvest: Aug 19 – Oct 28

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 Garfield County

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

Soil pH

Your soil pH (6.5–7.7) 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 Garfield County is excellent for Fennel (herb) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). 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 117-day season

Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.

For a dedicated fall crop, sow by Jul 13.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 339 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 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.3" 2" 💧 Light watering
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 1.6" 2.7" 🚿 Regular watering
Aug 4.3" 2" 2.3" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 2" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Garfield 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 ~975 GDD — county provides 1,521 GDD Excellent fit

Fennel (herb) Planting Timeline — Garfield County, UT

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors April 22 Apr 22 – May 6
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest July 22 Jul 22 – Sep 30
Fall Sowing July 13 Jul 13 – Jul 27

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

Month-by-Month Timeline

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

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 6a

📆 Growing Season

117 days in Garfield County

Growing Tips for Fennel (herb) in Garfield County

Direct sow Fennel (herb) outdoors after May 27 in Garfield 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.

Garfield County receives only 20" 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 Garfield County, UT?

Garfield County is in Zone 6a with an average last frost of May 27. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Garfield County, UT?

Garfield County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 27 and first fall frost is September 21.

🌱

Your Garfield County Garden Planner — Free

A 24-page printable planner built for Garfield County (Zone 6a). 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 Garfield County, UT. 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.