When to Plant Cabbage in Ontario
Published: April 24, 2026 · Updated: April 27, 2026
Extremely cold-hardy brassica — survives temperatures as low as -7°C (20°F). Start indoors 6–8 weeks before last frost, transplant 2–4 weeks before last frost, and also plant for fall harvest.
Cabbage grow well in this province with appropriate variety selection and standard Canadian planting timing.
Cabbage Planting Window for Ontario
Start seeds indoors: March 2–9 (varies by city — earliest in southern Ontario, latest on the Prairies)
Transplant outdoors: March 30–April 9 (after last frost in your city)
Minimum soil temperature: 7°C (45°F)
Days to harvest: 60–100 days
Sun requirement: Full sun (6+ hours)
Fall crop planting: August 9–19
⚠ Start cabbage indoors 6–8 weeks before last frost. Transplant 2–4 weeks before last frost. Very frost tolerant — withstands temperatures as low as 20°F. Also plant in late summer for fall harvest.
Ontario Cities — Cabbage Planting Dates
City-specific frost dates and cabbage planting windows for Ontario.
Growing Cabbage in Ontario
- Space plants 18 inches apart — crowding reduces head size and promotes fungal disease.
- Side-dress with nitrogen 3–4 weeks after transplanting to support rapid leaf formation.
- Harvest when heads feel firm; leave the root ball in the ground and small secondary heads may form.
- Fall cabbage sweetens after light frost — one of the best-tasting garden crops when harvested in October.
Companion Planting for Cabbage
In Ontario gardens, pair cabbage with Onion, Dill, Celery, Beet. Avoid planting near Tomato, Strawberry, Pepper, which compete with or inhibit cabbage growth.
Common Pests and Problems
Cabbage in Ontario are commonly affected by Cabbage Worm, Cabbage Looper, Aphid, Flea Beetle. Floating row covers installed at planting block most adult pests from laying eggs, and a weekly scouting routine catches infestations before they damage the crop.
Frequently Asked Questions
When should I plant cabbage in Ontario?
In Ontario (Canadian Zones 5b–6b), start seeds indoors around March 2 and transplant around March 30. Cabbage grow well in this province with appropriate variety selection and standard Canadian planting timing.
What is the best cabbage variety for Ontario?
Ontario gardeners should prioritise varieties bred for shorter seasons or Canadian climates. For cabbage in Canadian Zones 5b–6b, look for cultivars labelled under 100 days to maturity. Local nurseries and provincial seed exchanges curate varieties that ripen within Canadian frost-free windows.
How does Ontario's climate affect cabbage?
Ontario spans Canadian Zones 5b–6b with frost-free seasons ranging from roughly 153 to 195 days. Cabbage actually prefer the cooler spring and fall windows typical of Ontario, making them one of the most reliable crops in the province.
Can I grow cabbage in containers in Ontario?
Yes. Container growing on balconies and patios extends the viable growing area across every Canadian province. Dark-coloured containers warm up faster in spring and extend the season on both ends. Choose a 5-gallon or larger pot for cabbage and water daily during hot summer weather, since containers dry out quickly.
When is the first fall frost in Ontario?
First fall frost dates in Ontario range from October 15 in the coldest areas to November 1 in the warmest. For a fall cabbage crop, count back from your local first-frost date and plant around August 9–19.