When to Plant Fennel in Jefferson County, TX
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.
Jefferson County, Texas is in USDA Zone 9a. The average last spring frost is February 13 and the first fall frost is December 6, giving you a growing season of approximately 296 days.
At an elevation of 349 feet, Jefferson County receives approximately 64.9 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 101°F, so Fennel may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Fennel will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Fennel root diseases.
Jefferson County Soil Profile
Soil Type
Sandy Loam
Soil pH
5.4-6.5
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 Jefferson County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (5.4–6.5) overlaps with Fennel's range (5.5–7.0), though not a perfect match.
Soil Texture
Sandy soil in Jefferson County warms quickly in spring but drains fast. Fennel will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Fennel.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Sep 07 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 | — | 1.6" | 0" | ❄️ Dormant |
| Feb | 2.6" | 2.1" | 0.5" | 💧 Light watering |
| Mar | 2.6" | 4.4" | 0" | ✅ Rainfall sufficient |
| Apr | 2.6" | 6.3" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 9.8" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 10.7" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 8.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 6.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 6.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 4.4" | 0" | ✅ Rainfall sufficient |
| Nov | 2.6" | 2.1" | 0.5" | 💧 Light watering |
| Dec | 2.6" | 1.6" | 1" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in Jefferson 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 — Jefferson County, TX
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 2 | Jan 2 – Jan 16 |
| Transplant Outdoors | February 20 | Feb 20 – Mar 6 |
| Direct Sow | February 13 | Feb 13 – Mar 6 |
| Harvest | April 24 | Apr 24 – Jun 5 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Transplant Outdoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| 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: acceptable
🗺️ USDA Zone
Zone 9a
📆 Growing Season
296 days in Jefferson County
Growing Tips for Fennel in Jefferson County
Direct sow Fennel outdoors after February 13 in Jefferson County when soil has warmed and frost danger has passed.
Sandy soil in Jefferson County dries quickly — mulch Fennel with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 101°F in Jefferson County, provide afternoon shade for Fennel and water deeply in the morning.
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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Fennel in Other Locations
Frequently Asked Questions
When should I plant Fennel in Jefferson County, TX?
Jefferson County is in Zone 9a with an average last frost of February 13. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, TX?
Jefferson County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 13 and first fall frost is December 6.
Plan Your Garden with Confidence
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