When to Plant Fennel in Sublette County, WY
Your May game plan for Sublette County, Wyoming
Each item below is timed to Sublette County, Wyoming's frost dates and soil temperatures. Skip nothing, stress about nothing.
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.
Sublette County, Wyoming is in USDA Zone 4b. The average last spring frost is June 22 and the first fall frost is August 24, giving you a growing season of approximately 63 days.
At an elevation of 5,005 feet, Sublette County receives approximately 22.8 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.
Sublette County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
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 Sublette County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (6.7–7.8) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Sublette County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Fennel.
How to Plant Fennel
Plant Water Budget
Water stress score is 6/10 — 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 | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.6" | 0" | ❄️ Dormant |
| May | — | 2.5" | 0" | ❄️ Dormant |
| Jun | 2.6" | 1.5" | 1.1" | 💧 Light watering |
| Jul | 2.6" | 2.2" | 0.4" | 💧 Light watering |
| Aug | 2.6" | 2.1" | 0.5" | 💧 Light watering |
| Sep | — | 1.7" | 0" | ❄️ Dormant |
| Oct | — | 2" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Aug in Sublette 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 Planting Timeline — Sublette County, WY
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 20 | Apr 20 – May 4 |
| Transplant Outdoors | July 13 | Jul 13 – Jul 27 |
| Direct Sow | July 6 | Jul 6 – Jul 27 |
| Harvest | September 14 | Sep 14 – Oct 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors |
| June | — |
| July | Transplant Outdoors Direct Sow |
| August | — |
| 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 4b
📆 Growing Season
63 days in Sublette County
Growing Tips for Fennel in Sublette County
Direct sow Fennel outdoors after June 22 in Sublette County when soil has warmed and frost danger has passed.
Your 63.0-day growing season in Sublette County is tight for Fennel (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.
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
Check more plant combinations with our Companion Planting Checker →
Fennel in Other Locations
Frequently Asked Questions
When should I plant Fennel in Sublette County, WY?
Sublette County is in Zone 4b with an average last frost of June 22. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sublette County, WY?
Sublette County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is June 22 and first fall frost is August 24.
Your Sublette County Garden Planner — Free
A 24-page printable planner built for Sublette County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.