How to Grow Broccoli in Canada
How to grow broccoli in Canada starts with a question most guides skip: whether the crop fits your season at all. Broccoli needs 50-80 days to maturity, so compare that against your frost-free days before anything else. Start indoors 4-6 weeks before the last spring frost; direct sow again for a fall crop. Give them full sun and space them 45 cm (18 in) apart.
Does broccoli fit your Canadian season?
Subtract days to maturity from your frost-free days. If the answer is not comfortably positive, the crop will not finish — no amount of good technique fixes an arithmetic problem. Broccoli needs around 80 days from sowing or transplanting.
| Season band | Frost-free days | Days to maturity | Does it fit? |
|---|---|---|---|
|
Long season Zones 7-9 |
150-222 frost-free days | 50-80 days to maturity | Comfortable fit — room for a slow start. |
|
Medium season Zones 4-6 |
130-170 frost-free days | 50-80 days to maturity | Comfortable fit — room for a slow start. |
|
Short season Zones 2-3 |
90-130 frost-free days | 50-80 days to maturity | Fits, but with little margin. Choose a faster cultivar. |
When to plant broccoli in Canada
Timing runs from your local last spring frost: roughly 28 March in Vancouver, around 20 April to 10 May in Toronto, 3 May in Montreal, 7 May in Edmonton and 23 May in Calgary. Start indoors 4-6 weeks before the last spring frost; direct sow again for a fall crop.
Season extension for a short Canadian season
- Black plastic mulch laid two to three weeks before planting lifts soil temperature by several degrees — often the difference between a crop and a failure on the Prairies.
- Floating row cover adds roughly two to four weeks at each end of the season and keeps early pests off at the same time.
- Low tunnels and cold frames let hardy crops carry on well past the first frost, and let hardy sowings start earlier.
- Short-season cultivars are the cheapest form of season extension. Choosing one that matures two weeks earlier costs nothing and removes the risk entirely.
Soil and site
Fertile soil, pH 7.0-7.2 — maintaining pH above 7.0 is a critical cultural control to suppress clubroot infection.
Watering
Consistent moisture; tolerates light frost well.
Spacing and layout
Space broccoli 45 cm (18 in) apart. Crowding is the most common cause of disappointing yields — plants compete for light and water, and poor airflow between them raises disease pressure sharply.
Companion planting
Thyme, onion.
Common problems
Cabbage maggot — apply exclusion netting (0.6-1.3 mm mesh) immediately after transplanting as a physical barrier. Also watch for flea beetles and imported cabbageworm. Harvest heads tight and dense before yellow flowers open; store at 0C and 95-100% humidity.
Cold spring soil is behind more Canadian failures than any pest. Seed sown below its germination minimum rots rather than sprouts, and a warm-season transplant set out into cold ground is stunted for the rest of the season even if it survives. Waiting a week is almost always cheaper than re-sowing.
Turn growing broccoli into a written plan. The Canada Vegetable Garden Planner (printable PDF) has frost-date planning pages, bed layouts, crop rotation, a sowing log and a harvest tracker — 70 printable pages.
Frequently Asked Questions
Can I grow broccoli in Canada?
Broccoli needs around 80 days, so compare that against your frost-free days — roughly 90-130 on the Prairies, 130-170 through Central Canada and the Maritimes, and 150-222 on the coast.
When should I plant broccoli in Canada?
Start indoors 4-6 weeks before the last spring frost; direct sow again for a fall crop. Work from your local last frost — around 28 March in Vancouver, 20 April to 10 May in Toronto, 3 May in Montreal and 23 May in Calgary.
How far apart should broccoli be planted?
Space them 45 cm (18 in) apart.
What usually goes wrong with broccoli in Canada?
Cabbage maggot — apply exclusion netting (0.6-1.3 mm mesh) immediately after transplanting as a physical barrier. Also watch for flea beetles and imported cabbageworm. Harvest heads tight and dense before yellow flowers open; store at 0C and 95-100% humidity. Cold spring soil is the other common cause of failure — sowing before the soil has reached the crop's germination minimum causes seed to rot rather than sprout.
Last updated 25 August 2026
Tools That Help With This Crop
Use these links when the guide moves from reading into sowing, planting, watering, and keeping the crop healthy.
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.