When to Plant Fennel in Island County, WA
May in Island County, Washington — your action list
Here's what deserves your attention in Island County, Washington this month. Everything below is tailored to Zone 8b and timed around your local frost dates.
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Begin indoor sowing: fennel
These need a head start before your last frost (March 30). Sow into cells now so you're ready to transplant in a few weeks.
Before June arrives, get these ready
- First harvests: 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.
Island County, Washington is in USDA Zone 8b. The average last spring frost is March 30 and the first fall frost is November 3, giving you a growing season of approximately 218 days.
At an elevation of 9 feet, Island County receives approximately 45.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Fennel during the growing season.
Island County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.7
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 Island County
How your county's soil matches Fennel's growing requirements.
Soil pH
Your soil pH (5.6–6.7) is within Fennel's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Island County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.3%) — Fennel will thrive.
How to Plant Fennel
Succession Planting Fennel
Sow every 6.9 weeks. Last sowing by Aug 05 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 | — | 6.8" | 0" | ❄️ Dormant |
| Feb | — | 4.7" | 0" | ❄️ Dormant |
| Mar | 2.6" | 4.5" | 0" | ✅ Rainfall sufficient |
| Apr | 2.6" | 3.7" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 2.3" | 0.3" | 💧 Light watering |
| Jun | 2.6" | 1.6" | 1" | 💧 Light watering |
| Jul | 2.6" | 0.7" | 1.9" | 🚿 Regular watering |
| Aug | 2.6" | 0.8" | 1.8" | 🚿 Regular watering |
| Sep | 2.6" | 1.6" | 1" | 💧 Light watering |
| Oct | 2.6" | 4.2" | 0" | ✅ Rainfall sufficient |
| Nov | 2.6" | 7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 7.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Island 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 — Island County, WA
Fennel Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 9 | Feb 9 – Feb 23 |
| Transplant Outdoors | April 13 | Apr 13 – Apr 27 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 15 | Jun 15 – Jul 27 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| July | Harvest |
| 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: ideal
🗺️ USDA Zone
Zone 8b
📆 Growing Season
218 days in Island County
Growing Tips for Fennel in Island County
Direct sow Fennel outdoors after March 30 in Island 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 Island County, WA?
Island County is in Zone 8b with an average last frost of March 30. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.
What planting zone is Island County, WA?
Island County, Washington is in USDA Hardiness Zone 8b. The average last spring frost is March 30 and first fall frost is November 3.
Your Island County Garden Planner — Free
A 24-page printable planner built for Island County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.