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When to Plant Fennel (herb) in Williams County, OH

Williams County, Ohio Zone 6a May

Your May planting checklist for Williams County, Ohio

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

Avg. last frost April 29
Avg. first frost October 14
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
A few tasks this May that'll pay off in June
  • Starting indoors: fennel (herb)
  • First harvests: fennel (herb)

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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.

Williams County, Ohio is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 14, giving you a growing season of approximately 168 days.

At an elevation of 1,057 feet, Williams County receives approximately 39.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Fennel (herb) during the growing season.

Williams County, OH (Zone 6a) Moderate season
168 days
Last Spring Frost April 29
168 growing days
First Fall Frost October 14

Williams County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Recommended (50%) ✓ Fits season (42 days to spare)
Start indoors: Mar 25 Transplant: Apr 22 🍅 Harvest: Jun 24 – Sep 2
Safe Start (90%) ✓ Fits season (36 days to spare)
Start indoors: Apr 11 Transplant: May 9 🍅 Harvest: Jul 11 – Sep 19

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 Williams County

How your county's soil matches Fennel (herb)'s growing requirements.

Soil pH

Your soil pH (5.7–6.9) is within Fennel (herb)'s preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Fennel (herb) will thrive.

How to Plant Fennel (herb)

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

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Fennel (herb)

3
successive plantings in your 168-day season

Sow every 6.9 weeks. Last sowing by Jul 16 to harvest before frost.

For a dedicated fall crop, sow by Aug 05.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 18 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 4.1" 0.2" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 4.6" 0" ✅ Rainfall sufficient
Sep 4.3" 3.4" 0.9" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 3.1" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Williams 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) needs ~1,088 GDD — county provides 2,436 GDD Excellent fit

Fennel (herb) Planting Timeline — Williams County, OH

Fennel (herb) Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 15 Apr 15 – May 6
Harvest June 24 Jun 24 – Sep 2
Fall Sowing August 5 Aug 5 – Aug 19

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

168 days in Williams County

Growing Tips for Fennel (herb) in Williams County

Direct sow Fennel (herb) outdoors after April 29 in Williams 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

  • Tomatoes
  • Peppers
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Fennel (herb) in Williams County, OH?

Williams County is in Zone 6a with an average last frost of April 29. Plan your Fennel (herb) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Williams County, OH?

Williams County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 14.

🌱

Your Williams County Garden Planner — Free

A 24-page printable planner built for Williams 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.

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 Williams 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.