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When to Plant Fennel in Putnam County, OH

Putnam County, Ohio Zone 6a May

Putnam County, Ohio gardeners: here's your May plan

Here's what deserves your attention in Putnam County, Ohio this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost April 23
Avg. first frost October 22
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Plant out fennel

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

A few tasks this May that'll pay off in June
  • Starting indoors: 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.

Putnam County, Ohio is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 22, giving you a growing season of approximately 182 days.

At an elevation of 1,300 feet, Putnam County receives approximately 40.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Fennel to ensure they mature before fall.

Putnam County, OH (Zone 6a) Moderate season
182 days
Last Spring Frost April 23
182 growing days
First Fall Frost October 22
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Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 12
Recommended (50%) ✓ Fits season (63 days to spare)
Start indoors: Feb 26 Transplant: May 7 🍅 Harvest: Jul 9 – Aug 20
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Mar 11 Transplant: May 20 🍅 Harvest: Jul 22 – Sep 2

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 Putnam County

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

Soil pH

Your soil pH (6.3–6.7) is within Fennel's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.7%) — Fennel will thrive.

How to Plant Fennel

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

Succession Planting Fennel

3
successive plantings in your 182-day season

Sow every 6.9 weeks. Last sowing by Jul 24 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/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 1.8" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.6" 3.8" 0" ✅ Rainfall sufficient
May 2.6" 4.8" 0" ✅ Rainfall sufficient
Jun 2.6" 4.2" 0" ✅ Rainfall sufficient
Jul 2.6" 4.9" 0" ✅ Rainfall sufficient
Aug 2.6" 4.6" 0" ✅ Rainfall sufficient
Sep 2.6" 3.9" 0" ✅ Rainfall sufficient
Oct 2.6" 2.9" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 ~975 GDD — county provides 2,366 GDD Excellent fit

Fennel Planting Timeline — Putnam County, OH

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 26 Feb 26 – Mar 12
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 30 Apr 30 – May 21
Harvest July 9 Jul 9 – Aug 20

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
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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 6a

📆 Growing Season

182 days in Putnam County

Growing Tips for Fennel in Putnam County

Direct sow Fennel outdoors after April 23 in Putnam 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 Putnam County, OH?

Putnam County is in Zone 6a with an average last frost of April 23. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, OH?

Putnam County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 22.

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Your Putnam County Garden Planner — Free

A 24-page printable planner built for Putnam County (Zone 6a). 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 Putnam County, OH. 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.