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When to Plant Fennel in Converse County, WY

Converse County, Wyoming Zone 5a May

Top priorities for Converse County, Wyoming gardeners in May

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

Avg. last frost June 4
Avg. first frost September 18
Soil temp (4") 37°F
Watering High
Pest pressure Low
Daylight 14.5 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: fennel
  • Direct-sowing: fennel

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Florence fennel is grown for its swollen bulb-like stem base, which has a mild anise flavor. It is crisp raw in salads and sweet when roasted or braised.

Converse County, Wyoming is in USDA Zone 5a. The average last spring frost is June 4 and the first fall frost is September 18, giving you a growing season of approximately 106 days.

At an elevation of 6,089 feet, Converse County receives approximately 16.3 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Fennel to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Fennel successfully. Mulch heavily to conserve soil moisture.

Converse County, WY (Zone 5a) Short season
106 days
Last Spring Frost June 4
106 growing days
First Fall Frost September 18

Converse County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 26 Transplant: Jun 4 🍅 Harvest: Aug 6 – Sep 17
Recommended (50%) ✗ May not fit
Start indoors: Apr 9 Transplant: Jun 18 🍅 Harvest: Aug 20 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Apr 22 Transplant: Jul 1 🍅 Harvest: Sep 2 – Oct 14

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 Converse County

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

Soil pH

Your soil pH (6.6–8.3) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Fennel.

How to Plant Fennel

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

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Fennel

Fennel needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Fennel Needs Rainfall You Supplement Action
Jan 1.2" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 2.6" 1.2" 1.4" 🚿 Regular watering
Jul 2.6" 1.5" 1.1" 💧 Light watering
Aug 2.6" 1.5" 1.1" 💧 Light watering
Sep 2.6" 1.3" 1.3" 🚿 Regular watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Fennel 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 needs ~806 GDD — county provides 1,139 GDD Excellent fit

Fennel Planting Timeline — Converse County, WY

Fennel Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors June 18 Jun 18 – Jul 2
Direct Sow June 11 Jun 11 – Jul 2
Harvest August 20 Aug 20 – Oct 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

106 days in Converse County

Growing Tips for Fennel in Converse County

Direct sow Fennel outdoors after June 04 in Converse County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow in late summer for fall harvest to reduce bolting. Hill soil around bulbs as they enlarge. Harvest when bulbs are tennis-ball sized before they elongate.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Converse County, WY?

Converse County is in Zone 5a with an average last frost of June 4. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Converse County, WY?

Converse County, Wyoming is in USDA Hardiness Zone 5a. The average last spring frost is June 4 and first fall frost is September 18.

🌱

Your Converse County Garden Planner — Free

A 24-page printable planner built for Converse 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 Converse County, WY. 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.