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When to Plant Fennel in Seminole County, OK

Seminole County, Oklahoma Zone 7b May

May in the garden — Seminole County, Oklahoma

Your Seminole County, Oklahoma garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost March 31
Avg. first frost November 6
Soil temp (4") 69°F
Watering Moderate
Pest pressure Moderate
Daylight 13.8 hrs
  1. Get fennel seeds going inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

June prep starts now
  • 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.

Seminole County, Oklahoma is in USDA Zone 7b. The average last spring frost is March 31 and the first fall frost is November 6, giving you a growing season of approximately 220 days.

At an elevation of 961 feet, Seminole County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Fennel during the growing season.

Seminole County, OK (Zone 7b) Long season
220 days
Last Spring Frost March 31
220 growing days
First Fall Frost November 6

Seminole County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (99 days to spare)
Start indoors: Feb 3 Transplant: Apr 7 🍅 Harvest: Jun 9 – Jul 21
Recommended (50%) ✓ Fits season (101 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 28
Safe Start (90%) ✓ Fits season (103 days to spare)
Start indoors: Feb 25 Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 12

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 Seminole County

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

Soil pH

Your soil pH (6.7–7.5) is more alkaline than Fennel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Fennel.

How to Plant Fennel

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

Succession Planting Fennel

4
successive plantings in your 220-day season

Sow every 6.9 weeks. Last sowing by Aug 08 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.4″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 481 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 0.6" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 2.6" 1.4" 1.2" 💧 Light watering
Apr 2.6" 2.1" 0.5" 💧 Light watering
May 2.6" 3.2" 0" ✅ Rainfall sufficient
Jun 2.6" 3.3" 0" ✅ Rainfall sufficient
Jul 2.6" 2.4" 0.2" 💧 Light watering
Aug 2.6" 2.8" 0" ✅ Rainfall sufficient
Sep 2.6" 1.7" 0.9" 💧 Light watering
Oct 2.6" 1.3" 1.3" 🚿 Regular watering
Nov 2.6" 0.8" 1.8" 🚿 Regular watering
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Seminole 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 ~1,538 GDD — county provides 4,510 GDD Excellent fit

Fennel Planting Timeline — Seminole County, OK

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 10 Feb 10 – Feb 24
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 7 Apr 7 – Apr 28
Harvest June 16 Jun 16 – Jul 28

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: too_alkaline

🗺️ USDA Zone

Zone 7b

📆 Growing Season

220 days in Seminole County

Growing Tips for Fennel in Seminole County

Direct sow Fennel outdoors after March 31 in Seminole 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 Seminole County, OK?

Seminole County is in Zone 7b with an average last frost of March 31. Plan your Fennel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Seminole County, OK?

Seminole County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is March 31 and first fall frost is November 6.

🌱

Your Seminole County Garden Planner — Free

A 24-page printable planner built for Seminole 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 Seminole 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.