When to Plant Fennel (herb) in Yolo County, CA
What to do in May
May is a pivotal month for Yolo County, California gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Start harvesting fennel (herb)
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
To set up a strong June, finish these tasks
- First harvests: fennel (herb)
Herb fennel is grown for its aromatic leaves, stalks, and seeds rather than a bulb. It has a strong anise flavor and its flowers attract beneficial insects.
Yolo County, California is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.
At an elevation of 163 feet, Yolo County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Fennel (herb) may need afternoon shade and extra watering during peak heat.
Yolo 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 Yolo County
How your county's soil matches Fennel (herb)'s growing requirements.
Soil pH
Your soil pH (6.7–7.8) is more alkaline than Fennel (herb) prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Yolo County is excellent for Fennel (herb) — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Fennel (herb).
How to Plant Fennel (herb)
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Fennel (herb)
Sow every 6.9 weeks. Last sowing by Sep 04 to harvest before frost.
For a dedicated fall crop, sow by Oct 08.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Fennel (herb)
Fennel (herb) needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Fennel (herb) Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6" | 0" | ❄️ Dormant |
| Feb | 4.3" | 5.4" | 0" | ✅ Rainfall sufficient |
| Mar | 4.3" | 4" | 0.3" | 💧 Light watering |
| Apr | 4.3" | 2.3" | 2" | 💧 Light watering |
| May | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Jun | 4.3" | 0.1" | 4.2" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Oct | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Nov | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Dec | 4.3" | 5.1" | 0" | ✅ Rainfall sufficient |
Water needs are for active growing months only (Feb–Dec in Yolo County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Fennel (herb) 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 (herb) Planting Timeline — Yolo County, CA
Fennel (herb) Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 12 | Jan 12 – Jan 26 |
| Transplant Outdoors | February 2 | Feb 2 – Feb 16 |
| Direct Sow | January 19 | Jan 19 – Feb 9 |
| Harvest | April 6 | Apr 6 – Jun 15 |
| Fall Sowing | October 8 | Oct 8 – Oct 22 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Direct Sow |
| February | Transplant Outdoors Direct Sow |
| March | — |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 5.5–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 9b
📆 Growing Season
297 days in Yolo County
Growing Tips for Fennel (herb) in Yolo County
Direct sow Fennel (herb) outdoors after February 09 in Yolo County when soil has warmed and frost danger has passed.
Common pests for Fennel (herb) 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 spring or fall. Unlike Florence fennel, herb fennel does not form a bulb. Harvest fronds as needed and seeds when they turn brown. Self-sows readily.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Fennel (herb) in Other Locations
Frequently Asked Questions
When should I plant Fennel (herb) in Yolo County, CA?
Yolo County is in Zone 9b with an average last frost of February 9. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.
What planting zone is Yolo County, CA?
Yolo County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.
Your Yolo County Garden Planner — Free
A 24-page printable planner built for Yolo County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.