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When to Plant Fennel in Stormont-Dundas, ON

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.

Stormont-Dundas, Ontario is in USDA Zone 6a. The average last spring frost is April 20 and the first fall frost is October 17, giving you a growing season of approximately 180 days.

At an elevation of 196 feet, Stormont-Dundas receives approximately 35.5 inches of rainfall annually with predominantly clay loam soil. Summer highs average 79ยฐF, so choose short-season varieties of Fennel to ensure they mature before fall. Clay soil retains moisture well for Fennel, but amend with compost to improve drainage and prevent root rot.

Stormont-Dundas, ON (Zone 6a) Moderate season
180 days
Last Spring Frost April 20
180 growing days
First Fall Frost October 17

Stormont-Dundas Soil Profile

Soil Type

Clay Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (64 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 12
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Feb 18 Transplant: Apr 29 🍅 Harvest: Jul 1 – Aug 12
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Feb 18 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.

How to Plant Fennel

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

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

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 โ€” 1.5" 0" โ„๏ธ Dormant
Feb โ€” 1.7" 0" โ„๏ธ Dormant
Mar โ€” 2.1" 0" โ„๏ธ Dormant
Apr 2.6" 3.4" 0" โœ… Rainfall sufficient
May 2.6" 3.7" 0" โœ… Rainfall sufficient
Jun 2.6" 3.9" 0" โœ… Rainfall sufficient
Jul 2.6" 4.5" 0" โœ… Rainfall sufficient
Aug 2.6" 4.1" 0" โœ… Rainfall sufficient
Sep 2.6" 2.9" 0" โœ… Rainfall sufficient
Oct 2.6" 2.8" 0" โœ… Rainfall sufficient
Nov โ€” 2.7" 0" โ„๏ธ Dormant
Dec โ€” 2.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Aprโ€“Oct in Stormont-Dundas). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~694 GDD — county provides 1,665 GDD Excellent fit

Fennel Planting Timeline โ€” Stormont-Dundas, ON

Fennel Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 โ€“ Mar 9
Transplant Outdoors May 4 May 4 โ€“ May 18
Direct Sow April 27 Apr 27 โ€“ May 18
Harvest July 6 Jul 6 โ€“ Aug 17

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.6"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

180 days in Stormont-Dundas

Growing Tips for Fennel in Stormont-Dundas

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 Stormont-Dundas, ON?

Stormont-Dundas is in Zone 6a with an average last frost of April 20. Plan your Fennel planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Stormont-Dundas, ON?

Stormont-Dundas, Ontario is in USDA Hardiness Zone 6a. The average last spring frost is April 20 and first fall frost is October 17.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Stormont-Dundas gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.

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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 Stormont-Dundas, ON. Local conditions may vary. Last updated: April 2026.