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When to Plant Fennel in Madera County, CA

Madera County, California Zone 9a May

Your May planting checklist for Madera County, California

We've pulled the most time-sensitive tasks for Madera County, California this May and put them front and centre. Tackle them in order.

Avg. last frost April 18
Avg. first frost November 9
Soil temp (4") 78°F
Watering Critical
Pest pressure High
Daylight 14 hrs
  1. Fire up the seed-starting tray: fennel

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

Get ahead of June
  • First harvests: fennel

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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.

Madera County, California is in USDA Zone 9a. The average last spring frost is April 18 and the first fall frost is November 9, giving you a growing season of approximately 205 days.

At an elevation of 187 feet, Madera County receives approximately 14.5 inches of rainfall annually with predominantly loam soil. Summer highs average 104°F, so Fennel may need afternoon shade and extra watering during peak heat. With low rainfall, drip irrigation is essential for growing Fennel successfully. Mulch heavily to conserve soil moisture.

Madera County, CA (Zone 9a) Long season
205 days
Last Spring Frost April 18
205 growing days
First Fall Frost November 9
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Madera County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Start indoors: Feb 10 Transplant: Mar 31 🍅 Harvest: Jun 2 – Jul 14
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 7 Transplant: Apr 25 🍅 Harvest: Jun 27 – Aug 8
Safe Start (90%) ✓ Fits season (87 days to spare)
Start indoors: Apr 6 Transplant: May 25 🍅 Harvest: Jul 27 – Sep 7

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 Madera County

How your county's soil matches Fennel's growing requirements.

Soil pH

Your soil pH (6.2–7.8) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

The loam soil in Madera County is excellent for Fennel — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Fennel.

How to Plant Fennel

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Fennel

4
successive plantings in your 205-day season

Sow every 6.9 weeks. Last sowing by Aug 11 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.3″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 663 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 2.6" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.6" 1.3" 1.3" 🚿 Regular watering
May 2.6" 0.4" 2.2" 🚿 Regular watering
Jun 2.6" 0.1" 2.5" 🚿 Regular watering
Jul 2.6" 0" 2.6" 🚿 Regular watering
Aug 2.6" 0" 2.6" 🚿 Regular watering
Sep 2.6" 0.1" 2.5" 🚿 Regular watering
Oct 2.6" 0.7" 1.9" 🚿 Regular watering
Nov 2.6" 1.4" 1.2" 💧 Light watering
Dec 2.7" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Madera 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 needs ~2,100 GDD — county provides 5,740 GDD Excellent fit

Fennel Planting Timeline — Madera County, CA

Fennel Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 18 Apr 18 – May 9
Harvest June 27 Jun 27 – Aug 8

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

205 days in Madera County

Growing Tips for Fennel in Madera County

Direct sow Fennel outdoors after April 18 in Madera County when soil has warmed and frost danger has passed.

With summer highs reaching 104°F in Madera 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

Avoid Planting Near

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Madera County, CA?

Madera County is in Zone 9a with an average last frost of April 18. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madera County, CA?

Madera County, California is in USDA Hardiness Zone 9a. The average last spring frost is April 18 and first fall frost is November 9.

🌱

Your Madera County Garden Planner — Free

A 24-page printable planner built for Madera County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Madera County, CA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.