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When to Plant Celeriac in Stormont-Dundas, ON

Celeriac is a celery relative grown for its knobby, flavorful root rather than its stalks. It has a rich celery flavor and is excellent roasted, mashed, or in soups.

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 Celeriac to ensure they mature before fall. Clay soil retains moisture well for Celeriac, 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 (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 29 – Sep 2
Recommended (50%) ✓ Fits season (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 29 – Sep 2
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Mar 11 Transplant: Apr 15 🍅 Harvest: Jul 29 – Sep 2

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 Celeriac

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

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

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 115 gal / 100 sq ft

Monthly Watering Guide for Celeriac

Celeriac needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Celeriac 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 3.9" 3.4" 0.5" ๐Ÿ’ง Light watering
May 3.9" 3.7" 0.2" ๐Ÿ’ง Light watering
Jun 3.9" 3.9" 0" โœ… Rainfall sufficient
Jul 3.9" 4.5" 0" โœ… Rainfall sufficient
Aug 3.9" 4.1" 0" โœ… Rainfall sufficient
Sep 3.9" 2.9" 1" ๐Ÿ’ง Light watering
Oct 3.9" 2.8" 1.1" ๐Ÿ’ง Light watering
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.

Celeriac 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.

Celeriac needs ~1,018 GDD — county provides 1,665 GDD Excellent fit

Celeriac Planting Timeline โ€” Stormont-Dundas, ON

Celeriac Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 6 Apr 6 โ€“ Apr 27
Harvest August 3 Aug 3 โ€“ Sep 7
Fall Sowing August 8 Aug 8 โ€“ Aug 22

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.9"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

100โ€“120 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: N/A

๐Ÿ—บ๏ธ USDA Zone

Zone 6a

๐Ÿ“† Growing Season

180 days in Stormont-Dundas

Growing Tips for Celeriac in Stormont-Dundas

Common pests for Celeriac in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 10-12 weeks before last frost. Remove side roots as they develop to encourage a single large bulb. Harvest after a light frost for best flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celeriac in Stormont-Dundas, ON?

Stormont-Dundas is in Zone 6a with an average last frost of April 20. Plan your Celeriac 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.