When to Plant Kohlrabi in Canada — Sow Dates by Region
Fast, frost-hardy, and genuinely double-croppable — kohlrabi goes in early spring and again in late summer for fall. Sow dates by region, and how to catch it before it turns woody.
Kohlrabi is one of the easiest brassicas to fit into a Canadian season twice. It tolerates light frost like cabbage and broccoli, matures in as little as 45 days, and — unlike a lot of vegetables — genuinely rewards a spring-plus-fall double-crop rather than one long planting.
The one real risk is timing the harvest, not the sowing: leave it in the ground too long past tennis-ball size and it turns fibrous and woody, especially in warm weather.
Kohlrabi in Canada at a glance: Direct sow or transplant 2–4 weeks before last frost. Vancouver: mid-March. Toronto/Windsor: early-to-mid April. Ottawa/Montreal/Halifax: late April. Prairies: early-to-mid May. Matures in 45–60 days — sow again in late summer for a fall crop, and harvest at 5–8 cm before it turns woody.
When should you plant kohlrabi where you garden?
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🥦 Shop vegetable seeds at West Coast Seeds →Kohlrabi Sow Dates Across Canada
| Region (City) | Zone | Last Frost | Spring Sow | First Fall Frost | Fall Sow (10–12 wks back) |
|---|---|---|---|---|---|
| Coastal BC (Vancouver) | 8a | Mar 15 | Mar 1–15 | Nov 15 | Late Aug–early Sep |
| BC Interior (Kelowna) | 6b | May 5 | Apr 10–20 | Oct 5 | Mid-late July |
| Southern Ontario (Toronto) | 6b | Apr 20 | Apr 1–10 | Oct 15 | Late July–early Aug |
| SW Ontario (Windsor) | 7a | Apr 20 | Mar 25–Apr 5 | Oct 25 | Early-mid Aug |
| Eastern Ontario (Ottawa) | 5a | May 9 | Apr 15–25 | Oct 5 | Mid-late July |
| Quebec (Montreal) | 5b | May 9 | Apr 15–25 | Oct 5 | Mid-late July |
| Prairies (Calgary) | 3b | May 23 | Apr 25–May 5 | Sep 15 | Late June–early July |
| Prairies (Edmonton) | 4a | May 14 | Apr 20–30 | Sep 20 | Early-mid July |
| Prairies (Winnipeg) | 3a | May 19 | Apr 25–May 5 | Sep 22 | Early-mid July |
| Maritimes (Halifax) | 6a | May 10 | Apr 15–25 | Oct 15 | Late July–early Aug |
Common Kohlrabi Problems in Canada
Woody, fibrous bulbs
By far the most common complaint, and it's a timing issue rather than a growing problem. Harvest at 5–8 cm — check plants every few days once they approach size rather than waiting for a calendar date.
Bolting (premature flowering)
A cold snap hitting larger transplants can trigger early flowering, the same vernalization response cabbage shares. Transplant while seedlings are still young and small, especially for an early spring planting.
Cabbage worms and flea beetles
Kohlrabi shares the usual brassica pests. Floating row cover from transplant onward is the simplest prevention and doubles as light frost protection for the fall crop.
Frequently Asked Questions
When should I plant kohlrabi in Canada?
2–4 weeks before your last frost date. Vancouver: mid-March. Toronto/Windsor: early April. Prairies: early-to-mid May.
Can I get two kohlrabi harvests in one season?
Yes — sow again in mid-to-late summer, 10–12 weeks before your first fall frost, for a second, often sweeter, crop.
When do I harvest kohlrabi?
At 5–8 cm across — leaving it longer turns the bulb woody, especially in warm weather.