When to Plant Fennel in Sullivan County, PA
May in the garden — Sullivan County, Pennsylvania
Each item below is timed to Sullivan County, Pennsylvania's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Time to transplant fennel
Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.
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Put fennel seeds straight in the ground
Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.
June prep starts now
- Starting indoors: fennel
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.
Sullivan County, Pennsylvania is in USDA Zone 6a. The average last spring frost is May 1 and the first fall frost is October 17, giving you a growing season of approximately 169 days.
At an elevation of 560 feet, Sullivan County receives approximately 44.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Fennel during the growing season.
Sullivan County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.8
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 Sullivan County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (4.9–6.8) overlaps with Fennel's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Sullivan County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.9%). Annual compost additions will help Fennel.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Jul 19 to harvest before frost.
Plant Water Budget
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 | — | 3.1" | 0" | ❄️ Dormant |
| Feb | — | 2.6" | 0" | ❄️ Dormant |
| Mar | — | 4.2" | 0" | ❄️ Dormant |
| Apr | — | 4.1" | 0" | ❄️ Dormant |
| May | 2.6" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.6" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.6" | 4.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.6" | 3.8" | 0" | ✅ Rainfall sufficient |
| Sep | 2.6" | 3.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.6" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.1" | 0" | ❄️ Dormant |
| Dec | — | 3.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Sullivan 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 — Sullivan County, PA
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 6 | Mar 6 – Mar 20 |
| Transplant Outdoors | May 15 | May 15 – May 29 |
| Direct Sow | May 8 | May 8 – May 29 |
| Harvest | July 17 | Jul 17 – Aug 28 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| 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 6a
📆 Growing Season
169 days in Sullivan County
Growing Tips for Fennel in Sullivan County
Direct sow Fennel outdoors after May 01 in Sullivan 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
Check more plant combinations with our Companion Planting Checker →
Fennel in Other Locations
Frequently Asked Questions
When should I plant Fennel in Sullivan County, PA?
Sullivan County is in Zone 6a with an average last frost of May 1. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Sullivan County, PA?
Sullivan County, Pennsylvania is in USDA Hardiness Zone 6a. The average last spring frost is May 1 and first fall frost is October 17.
Your Sullivan County Garden Planner — Free
A 24-page printable planner built for Sullivan 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.