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When to Plant Fennel in Madison County, OH

Madison County, Ohio Zone 6b August

Top priorities for Madison County, Ohio gardeners in August

Your garden in Madison County, Ohio is working on a schedule, even when you're not. Here's where you should be this August.

Avg. last frost April 22
Avg. first frost October 20
Soil temp (4") 79°F
Watering Low
Pest pressure High
Daylight 13.6 hrs
  1. Basket week: fennel

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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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.

Madison County, Ohio is in USDA Zone 6b. The average last spring frost is April 22 and the first fall frost is October 20, giving you a growing season of approximately 181 days.

At an elevation of 674 feet, Madison County receives approximately 35.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Fennel during the growing season.

Madison County, OH (Zone 6b) Moderate season
181 days
Last Spring Frost April 22
181 growing days
First Fall Frost October 20

Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.1

Drainage

Well Drained

Fennel Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Start indoors: Feb 19 Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 13
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Feb 25 Transplant: May 6 🍅 Harvest: Jul 8 – Aug 19
Safe Start (90%) ✓ Fits season (56 days to spare)
Start indoors: Mar 14 Transplant: May 23 🍅 Harvest: Jul 25 – Sep 5

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 Madison County

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

Soil pH

Your soil pH (5.8–7.1) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Fennel will thrive.

How to Plant Fennel

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

Succession Planting Fennel

3
successive plantings in your 181-day season

Sow every 6.9 weeks. Last sowing by Jul 22 to harvest before frost.

Fennel Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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 1.3" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.6" 3.3" 0" ✅ Rainfall sufficient
May 2.6" 3.8" 0" ✅ Rainfall sufficient
Jun 2.6" 4.7" 0" ✅ Rainfall sufficient
Jul 2.6" 4.5" 0" ✅ Rainfall sufficient
Aug 2.6" 3.9" 0" ✅ Rainfall sufficient
Sep 2.6" 3.2" 0" ✅ Rainfall sufficient
Oct 2.6" 2.4" 0.2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Madison 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 ~1,088 GDD — county provides 2,624 GDD Excellent fit

Fennel Planting Timeline — Madison County, OH

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 25 Feb 25 – Mar 11
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest July 8 Jul 8 – Aug 19

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Direct Sow
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 6b

📆 Growing Season

181 days in Madison County

Growing Tips for Fennel in Madison County

Direct sow Fennel outdoors after April 22 in Madison 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

  • Tomatoes
  • Peppers
  • Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel in Madison County, OH?

Madison County is in Zone 6b with an average last frost of April 22. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, OH?

Madison County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 22 and first fall frost is October 20.

🌱

Your Madison County Garden Planner — Free

A 22-page printable planner built for Madison County (Zone 6b). 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 Madison County, OH. Local conditions may vary. Last updated: August 2026.

Sources & credits

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