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When to Plant Fennel in Vanderburgh County, IN

Vanderburgh County, Indiana Zone 7a May

Your May planting checklist for Vanderburgh County, Indiana

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost April 7
Avg. first frost October 29
Soil temp (4") 64°F
Watering Low
Pest pressure Low
Daylight 14.1 hrs
  1. Time to start fennel inside

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

Before June arrives, get these ready
  • 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.

Vanderburgh County, Indiana is in USDA Zone 7a. The average last spring frost is April 7 and the first fall frost is October 29, giving you a growing season of approximately 205 days.

At an elevation of 901 feet, Vanderburgh County receives approximately 40.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 87°F, providing good warmth for Fennel during the growing season.

Vanderburgh County, IN (Zone 7a) Long season
205 days
Last Spring Frost April 7
205 growing days
First Fall Frost October 29

Vanderburgh County Soil Profile

Soil Type

Silt Loam

Soil pH

6-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🍅 Harvest: Jun 16 – Jul 28
Recommended (50%) ✓ Fits season (86 days to spare)
Start indoors: Feb 17 Transplant: Apr 21 🍅 Harvest: Jun 23 – Aug 4
Safe Start (90%) ✓ Fits season (91 days to spare)
Start indoors: Mar 3 Transplant: May 5 🍅 Harvest: Jul 7 – Aug 18

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 Vanderburgh County

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

Soil pH

Your soil pH (6.0–6.8) is within Fennel's preferred range (5.5–7.0).

Soil Texture

The silt loam soil in Vanderburgh 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 205-day season

Sow every 6.9 weeks. Last sowing by Jul 31 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.8″/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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.6" 4.2" 0" ✅ Rainfall sufficient
May 2.6" 5" 0" ✅ Rainfall sufficient
Jun 2.6" 5.1" 0" ✅ Rainfall sufficient
Jul 2.6" 3.9" 0" ✅ Rainfall sufficient
Aug 2.6" 3.8" 0" ✅ Rainfall sufficient
Sep 2.6" 3.5" 0" ✅ Rainfall sufficient
Oct 2.6" 3.1" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Vanderburgh 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 ~1,144 GDD — county provides 3,126 GDD Excellent fit

Fennel Planting Timeline — Vanderburgh County, IN

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 – Mar 3
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 14 Apr 14 – May 5
Harvest June 23 Jun 23 – Aug 4

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

Month-by-Month Timeline

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

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 7a

📆 Growing Season

205 days in Vanderburgh County

Growing Tips for Fennel in Vanderburgh County

Direct sow Fennel outdoors after April 07 in Vanderburgh 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 Vanderburgh County, IN?

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

What planting zone is Vanderburgh County, IN?

Vanderburgh County, Indiana is in USDA Hardiness Zone 7a. The average last spring frost is April 7 and first fall frost is October 29.

🌱

Your Vanderburgh County Garden Planner — Free

A 24-page printable planner built for Vanderburgh County (Zone 7a). 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 Vanderburgh County, IN. 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.