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When to Plant Fennel in Ottawa County, OH

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.

Ottawa County, Ohio is in USDA Zone 6b. The average last spring frost is April 25 and the first fall frost is October 25, giving you a growing season of approximately 183 days.

At an elevation of 1,264 feet, Ottawa County receives approximately 31.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Fennel during the growing season.

Ottawa County, OH (Zone 6b) Moderate season
183 days
Last Spring Frost April 25
183 growing days
First Fall Frost October 25

Ottawa County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Monthly Watering Guide for Fennel

Fennel 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 Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 3.9" 0.4" 💧 Light watering
Jul 4.3" 3.3" 1" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.2" 2.1" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Ottawa County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Fennel Planting Timeline — Ottawa County, OH

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest July 11 Jul 11 – Aug 22

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
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

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6b

📆 Growing Season

183 days in Ottawa County

Growing Tips for Ottawa County

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 Ottawa County, OH?

Ottawa County is in Zone 6b with an average last frost of April 25. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ottawa County, OH?

Ottawa County, Ohio is in USDA Hardiness Zone 6b. The average last spring frost is April 25 and first fall frost is October 25.

🌱

Your Ottawa County Garden Planner — Free

A 22-page printable planner built for Ottawa 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.

Instant PDF download. No spam, unsubscribe any time.

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

Sources & credits

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