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When to Plant Fennel in Coal County, OK

Coal County, Oklahoma Zone 7b May

Coal County, Oklahoma gardeners: here's your May plan

May is a pivotal month for Coal County, Oklahoma gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 28
Avg. first frost November 2
Soil temp (4") 69°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Start fennel under lights

    You're about 23 weeks out from your last frost — the perfect window to get these germinating indoors.

Coming up in June — start thinking about
  • 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.

Coal County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 28 and the first fall frost is November 2, giving you a growing season of approximately 219 days.

At an elevation of 892 feet, Coal County receives approximately 28.5 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Fennel during the growing season.

Coal County, OK (Zone 7b) Long season
219 days
Last Spring Frost March 28
219 growing days
First Fall Frost November 2

Coal County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (102 days to spare)
Start indoors: Jan 31 Transplant: Apr 4 🍅 Harvest: Jun 6 – Jul 18
Recommended (50%) ✓ Fits season (100 days to spare)
Start indoors: Feb 7 Transplant: Apr 11 🍅 Harvest: Jun 13 – Jul 25
Safe Start (90%) ✓ Fits season (102 days to spare)
Start indoors: Feb 26 Transplant: Apr 30 🍅 Harvest: Jul 2 – Aug 13

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 Coal County

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

Soil pH

Your soil pH (6.5–7.2) overlaps with Fennel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.0%) — Fennel will thrive.

How to Plant Fennel

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

Succession Planting Fennel

4
successive plantings in your 219-day season

Sow every 6.9 weeks. Last sowing by Aug 04 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 125 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 0.7" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 2.6" 1.6" 1" 💧 Light watering
Apr 2.6" 2.7" 0" ✅ Rainfall sufficient
May 2.6" 4.2" 0" ✅ Rainfall sufficient
Jun 2.6" 4.8" 0" ✅ Rainfall sufficient
Jul 2.6" 3.7" 0" ✅ Rainfall sufficient
Aug 2.6" 3.6" 0" ✅ Rainfall sufficient
Sep 2.6" 2.8" 0" ✅ Rainfall sufficient
Oct 2.6" 1.9" 0.7" 💧 Light watering
Nov 2.6" 1" 1.6" 🚿 Regular watering
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Coal 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 ~1,256 GDD — county provides 3,668 GDD Excellent fit

Fennel Planting Timeline — Coal County, OK

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors April 11 Apr 11 – Apr 25
Direct Sow April 4 Apr 4 – Apr 25
Harvest June 13 Jun 13 – Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

219 days in Coal County

Growing Tips for Fennel in Coal County

Direct sow Fennel outdoors after March 28 in Coal 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 Coal County, OK?

Coal County is in Zone 7b with an average last frost of March 28. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Coal County, OK?

Coal County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 28 and first fall frost is November 2.

🌱

Your Coal County Garden Planner — Free

A 24-page printable planner built for Coal County (Zone 7b). 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 Coal County, OK. 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.