When to Plant Fennel in Phillips County, MT
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.
Phillips County, Montana is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 21, giving you a growing season of approximately 126 days.
At an elevation of 6,886 feet, Phillips County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 80°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.
Phillips County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.6
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 Phillips County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (6.7–7.6) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Phillips County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Fennel.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jun 23 to harvest before frost.
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.9" | 0" | ❄️ Dormant |
| May | 2.6" | 2.4" | 0.2" | 💧 Light watering |
| Jun | 2.6" | 1.4" | 1.2" | 💧 Light watering |
| Jul | 2.6" | 1.6" | 1" | 💧 Light watering |
| Aug | 2.6" | 2" | 0.6" | 💧 Light watering |
| Sep | 2.6" | 1.4" | 1.2" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.3" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Phillips 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 — Phillips County, MT
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | June 8 | Jun 8 – Jun 22 |
| Direct Sow | June 1 | Jun 1 – Jun 22 |
| Harvest | August 10 | Aug 10 – Sep 21 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | — |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Harvest |
| September | Harvest |
| October | — |
| 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 4a
📆 Growing Season
126 days in Phillips County
Growing Tips for Fennel in Phillips County
Direct sow Fennel outdoors after May 18 in Phillips 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
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Check more plant combinations with our Companion Planting Checker →
Fennel in Other Locations
Frequently Asked Questions
When should I plant Fennel in Phillips County, MT?
Phillips County is in Zone 4a with an average last frost of May 18. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Phillips County, MT?
Phillips County, Montana is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 21.
Plan Your Garden with Confidence
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