How to Grow Cauliflower Canada

On this page
  1. Cauliflower (Brassica oleracea Botrytis Group)
  2. Regional Planting Calendar
  3. Quick Facts
  4. At a Glance
  5. Soil & Growing Conditions
  6. Growth Stages
  7. Harvest & Storage
  8. Diseases
  9. Pests
  10. Nutrient Issues
  11. Companion Planting
  12. Cauliflower, Seed to Harvest
  13. Plan your Cauliflower planting
  14. Growing Cauliflower in another region
  15. Sources
  16. Frequently Asked Questions

In Canada, cauliflower planted out mid March to early April, and is ready to harvest 60–70 days after planting out.

Timing is the decision that matters most in Canada: there are 6 separate regional planting out windows, ranging from mid March in Pacific Coastal Mild to early June in Far North & Alpine.

The short answer

Plant out
Mid March to early April
Ready in
60–70 days after planting out
Site
soil pH 6.5
Biggest risk
White blister

Core growing advice on this page is checked against named horticultural sources — see References.

Cauliflower (Brassica oleracea Botrytis Group)

A white cauliflower curd nestled in the plant's blue-green leaves, seen from above. Photo: Rasbak, CC BY-SA 3.0, via Wikimedia Commons.

11 sources cited · Verified

Regional Planting Calendar

Region Plant out
Pacific Coastal Mild derived mid March to early April
Central Continental derived late April to mid May
Inland Valleys & Southern Lakes derived late April to mid May
Atlantic Maritime derived early May to late May
Prairies & Short-Season Continental derived late May to early June
Far North & Alpine derived early June to mid June

Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.

Pacific Coastal Mild - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 18 March (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 18 March to 1 April. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Central Continental - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 30 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 30 April to 14 May. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Inland Valleys & Southern Lakes - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 30 April (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 30 April to 14 May. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Atlantic Maritime - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 7 May (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 7 May to 21 May. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Prairies & Short-Season Continental - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 21 May (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 21 May to 4 June. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Far North & Alpine - detail & sources

DERIVED from this region's own frost normal, not quoted for the region. Transplant once daytime temperatures reach 10°C and night temperatures are not below -2°C for several nights in a row; mature brassicas are frost tolerant but young transplants much less so. Applied to a mean last frost of 5 June (NOAA NCEI 1991-2020 for the USA; Environment and Climate Change Canada normals for Canada), that gives 5 June to 19 June. Your own local frost date is what matters — a region spans a range, and this figure comes from one representative station within it.

Quick Facts

Factor Value
Soil pH 6.5 - 6.5
Germination temp 24°C
Optimal growing temp 10-25°C
Minimum survivable temp -5°C
Time to harvest 60-70 days after planting out
Drainage RHS: cauliflowers grow well in soil with a pH of about 6.5; chalk, clay, loam or sand soil types, rich and well-drained with high moisture-holding capacity.
Lifecycle annual/biennial, grown as annual
Edible parts flower buds (curd)

At a Glance

Brassica oleracea Botry… Cauliflower White blister Club root Damping-off (seedling c… Alternaria leaf blight Downy mildew (general) Black rot of brassicas Cabbage root fly (US: c… Cabbage caterpillars Flea beetles Mealy cabbage aphid Slugs Cabbage webworm Cross-striped cabbagewo… Diamondback moth caterp… Cabbage looper Imported cabbageworm Harlequin bug DISEASES PESTS

Soil & Growing Conditions

A whole cauliflower plant in a garden bed, its small creamy curd just visible at the centre of a rosette of large leaves — “Brassica oleracea var. botrytis” by Sanja565658 is licensed under CC BY-SA 3.0. Source: Wikimedia Commons
“Brassica oleracea var. botrytis” by Sanja565658 is licensed under CC BY-SA 3.0. Source: Wikimedia Commons.

Soil pH range

6.5 6.5

Span reflects genuine variation between the cited authorities, not a single agreed figure.

Growth Stages

Stage BBCH Notes
Germination & seedling 0 Cauliflower is raised from seed, sown thinly about 1.5cm (¾in) deep in modules or a seedbed rather than sown direct, so plants can be grown on and transplanted without a check to growth. RHS: sow indoors from late winter for early summer crops, or outdoors from spring; Clemson notes transplants are produced in about five to eight weeks. Keep the compost consistently moist and harden plants off before planting out — any check at this stage can trigger premature "buttoning" (tiny, useless curds).
Vegetative growth (transplanting & leafing) 3 Transplant when plants are 10–15cm (4–6in) tall, at about six weeks old, into firm, fertile, moisture-retentive soil — loose or poor soil gives small, distorted curds. Spacing depends on type: RHS spaces summer/autumn cauliflowers 45–60cm (18–24in) apart in rows 60cm (24in) apart, winter/spring types about 70cm (28in) each way, and mini-caulis just 15cm (6in) apart; Clemson sets plants 18in apart in rows 3ft apart. Water in well, keep weed-free, feed with nitrogen for strong leaf growth, and net against pigeons and cabbage white caterpillars.
Curd formation (heading) 4 As the plant matures the growing point forms a tight curd of immature flower buds. Even, uninterrupted moisture is critical now: RHS says cauliflowers grow best in soil that is damp at all times — dry soil can stop growth so the head fails to form correctly — and Clemson stresses plants should never be short of water or fertiliser. To keep white curds pale, snap and fold the inner leaves over the curd (or tie them) to shade it from sun; in winter, bunch and tie the leaves over the curd and use fleece to protect it from hard frost.
Maturity & harvest 8 Cut the curd as soon as it is large enough while still firm and compact — RHS warns that once the head starts to separate it is past its best; Clemson gives roughly 60–70 days from transplanting, though winter types take far longer (three to six months from sowing overall). Harvest in the cool of the morning by cutting through the stem with a sharp knife, leaving a few wrapper leaves around the curd to protect it. Curds do not store for long, so cut as needed or keep in the fridge for a few days.

Harvest & Storage

A freshly cut whole cauliflower head with trimmed pale-green wrapper leaves, on a plain background — “Chou-fleur 02” by Coyau is licensed under CC BY-SA 3.0. Source: Wikimedia Commons
“Chou-fleur 02” by Coyau is licensed under CC BY-SA 3.0. Source: Wikimedia Commons.

When to pick: Harvest as soon as the head is large enough, while still firm and compact; do not wait until the head starts to separate

Diseases

White blister

Albugo candida

RHS cauliflower guide names white blister among named problems.

Plasmodiophora brassicae

Damping-off (seedling collapse)
medium

Rhizoctonia solani

Damping-off (seedling collapse at soil line); Wilting with chlorotic, dropping leaves

Seed that rots before emergence, or seedlings collapsing at the soil line. A transplant-raising problem more than a bed problem: use fresh commercial mix, containers cleaned with a 10% bleach solution, and…

Alternaria leaf blight
medium

Alternaria dauci

Brown circular spots with concentric target rings, and small dark stem lesions on seedlings. Active between 60 and 90°F in moist conditions and overwinters on crop residue, so clearing the bed at season end plus a…

Downy mildew (general)
medium

Grey mould on the underside of the leaf with yellowing, later browning, on the upper surface directly above it. A moisture problem rather than a heat one: space widely so leaves dry, and water at soil level.

Black rot of brassicas
high

Xanthomonas campestris pv. campestris

Yellow V-shaped lesions cutting in from the leaf margin, with the point of the V aimed at a vein; the veins blacken and the rot can reach the stem. Seed- and transplant-borne, so it usually arrives on bought plants…

Pests

Cabbage root fly (US: cabbage maggot)

Delia radicum

RHS cauliflower guide names cabbage root fly among named pests.

Cabbage caterpillars

Pieris brassicae; Pieris rapae; Pieris napi; Mamestra brassicae; Plutella xylostella

RHS cauliflower guide names cabbage caterpillars among named pests.

Flea beetles

Chrysomelidae: Alticini (various spp.)

RHS cauliflower guide names flea beetles on brassicas among named pests.

Mealy cabbage aphid

Brevicoryne brassicae

RHS cauliflower guide names mealy cabbage aphid among named pests.

Slugs

Gastropoda (slugs, various spp.)

RHS cauliflower guide names slugs and snails among named pests.

Cabbage webworm
medium

Hellula rogatalis

Small, tan and brown striped with a dark head. It webs itself into the new growth for protection and attacks the buds and growing point, which causes lateral budding and can ruin a plant that would otherwise have made…

Cross-striped cabbageworm
medium

Evergestis rimosalis

Alternating black and white stripes across the back with a yellow stripe along the side, reaching about three-quarters of an inch. It hatches in masses and can rapidly skeletonise a plant, then drops to pupate just…

Diamondback moth caterpillar
high

Plutella xylostella

Clemson calls it "the most serious insect pest of brassica crops in South Carolina" despite being small, up to half an inch. The tell is a window-pane effect: the caterpillar eats the underside and leaves the upper…

Cabbage looper
high

Trichoplusia ni

Up to 1.5 inches, moving in the distinctive looping gait, and it makes far bigger holes than diamondback moth -- Clemson puts one looper at roughly the damage of five diamondback larvae, so finding one matters more.…

Imported cabbageworm
medium

Pieris rapae

About an inch long and recognisable by its fuzzy appearance; Clemson rates it at about two-thirds the damage of a looper. It pupates in a chrysalis on the host plant, so it can be removed with the plant.

Harlequin bug
medium

Murgantia histrionica

A shield bug with a striking reddish-orange and black pattern; the eggs look like tiny black-and-white striped barrels laid in rows, which makes them easy to find and destroy. Piercing-sucking feeding leaves distinct…

Nutrient Issues

Boron (B)

deficiency

Correction

RHS names cauliflower among the boron-sensitive vegetables. In cauliflower, calabrese and cabbage the symptoms are hollow stem and a browning curd. Boron is less available above pH 7, so avoid liming already-alkaline ground; test soil pH rather than adding boron blind, as the margin between deficiency and toxicity is narrow.

Molybdenum (Mo)

deficiency

Correction

RHS names cauliflowers specifically: molybdenum deficiency causes "whiptail", elongated twisted leaves in which only the midrib develops, while the curd stays white (distinguishing it from boron deficiency, which browns the curd). Worse on acid soil, where less molybdenum is available to roots. Long term, test and correct soil pH before growing brassicas; short term, apply fritted trace elements containing molybdenum before sowing or planting.

Companion Planting

avoid shared disease

Brassica oleracea Italica Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica napus Napobrassica Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Gemmifera Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Raphanus sativus

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Acephala Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica rapa Rapifera Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

avoid shared disease

Brassica oleracea Capitata Group

Plasmodiophora brassicae produces resting spores that contaminate the soil and remain viable for many years, so any brassica following an infected crop is re-infected from the ground itself. Keep every brassica -- including radish, swede and turnip, which gardeners often forget are brassicas --…

Plan your Cauliflower planting

When to sow and plant Cauliflower depends on your own frost dates. Check the Canada vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Cauliflower in another region

Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.

Sources

  1. Canadian source: start transplants 5-6 weeks before planting out; germinates in 5-6 days at 24°C; transplant once days reach 10°C and nights hold above -2°C for several nights running, in Saskatoon any time after 13 May; 30-45 cm in row, 60-85 cm between rows; mature brassicas frost tolerant but young transplants much less so; blanch by tying outer leaves; harvest firm and dense; store near 0°C at high humidity.

These source is specific to this region. The full list of 11 sources behind this guide (Clemson Cooperative Extension, FAO EcoCrop, Ohio State University Extension (Ohioline) and others) is in the references of our UK guide to cauliflower; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

When should I plant cauliflower out in Canada?

In Pacific Coastal Mild, from mid March. In Far North & Alpine, wait until early June. Treat these as a guide rather than a fixed date — the governing rule is to plant out only once frost risk has passed and temperatures are reliably warm enough.

How long does cauliflower take to grow?

Typically 60–70 days after planting out, depending on cultivar and growing conditions.

What soil pH does cauliflower need?

A pH of about 6.5–6.5. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.

What problems affect cauliflower?

Our data links 6 diseases and 11 pests to this crop. See the sections above for each one and how to manage it.

Plan next season before the problems start

Short-season growing is arithmetic before it is technique: days to maturity against frost-free days decides what will finish at all. The Canada Garden Planner does that subtraction for your region before you sow.

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Instant PDF download · Written for Canadian growing conditions

SoilCommander Editorial Team — under the direction of Nitin Sharma, Co-Founder

Every growing guide is checked against RHS, USDA Cooperative Extension, and other named horticultural authorities before publishing.

How this guide is put together

The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against Canadian hardiness-zone and frost-date data, with provincial agriculture and university extension sources cited directly where one exists for a crop. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.

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