When to Plant Cabbage in Hamilton, ON
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.
Hamilton's Canadian Zone 6b (USDA 6a) climate benefits from the Niagara Escarpment's moderating effect. The 189 frost-free days make this one of the warmest regions in Ontario, with some sheltered sites reaching near-Zone 7 microclimate conditions. Melons, peppers, and eggplant succeed reliably where they would struggle elsewhere.
Cabbage Planting Calendar for Hamilton
Start seeds indoors: March 4–11
Transplant outdoors: April 1–11
Harvest window: May 31 – July 10
Minimum soil temperature: 7°C (45°F)
Days to harvest: 60–100 days
Sun requirement: Full sun (6+ hours)
Fall crop planting: August 5–15 (harvest October 4)
⚠ 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.
Hamilton Climate Notes
Hamilton/Niagara is the warmest part of Ontario. Near-Zone 7 microclimate conditions exist in sheltered sites near the escarpment. This region is Ontario's most productive for heat-loving crops including melons, eggplant, and peppers.
Growing Tips for Cabbage
- 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 in Hamilton
Pair cabbage with Onion, Dill, Celery, Beet for mutual benefit. Avoid planting near Tomato, Strawberry, Pepper, which compete with or inhibit cabbage growth.
Pests and Problems to Watch in Hamilton
The most common pest and disease pressure on cabbage in Hamilton comes from Cabbage Worm, Cabbage Looper, Aphid, Flea Beetle. Floating row covers through the first 4–6 weeks after planting block adult pests from laying eggs, and a weekly scouting routine catches infestations before they damage the crop.
Other Ontario Cities
Frequently Asked Questions
When do I plant cabbage in Hamilton?
Hamilton's last spring frost is around April 22. Start seeds indoors March 4–11. Transplant outdoors April 1–11.
What Canadian hardiness zone is Hamilton?
Hamilton is in Canadian Zone 6b (USDA equivalent 6a). The Niagara Escarpment temperate climate delivers 189 frost-free days from April 22 to October 28, which shapes every planting date in the local calendar.
How long is Hamilton's growing season?
Hamilton has 189 frost-free days — from April 22 in spring to October 28 in fall. That is more than enough time to finish a full cabbage crop (60–100 days to maturity) before the first fall frost.
Can I grow cabbage in containers in Hamilton?
Yes. Container growing on balconies and decks is practical in Hamilton — choose a 5-gallon or larger dark-coloured container to warm the root zone, use a high-quality potting mix, and water daily during hot summer weather. In milder climates, containers extend both spring and fall windows by several weeks.
What is the first fall frost in Hamilton?
Hamilton's average first fall frost is October 28. For a fall cabbage crop, plant around August 5–15 so plants mature before the first killing frost.