How to Grow Kale in Canada

On this page
  1. Kale (Brassica oleracea Acephala Group)
  2. Quick Facts
  3. At a Glance
  4. When to plant in Canada
  5. Does Kale Regrow After Cutting? (And Is It Too Late t...
  6. Growth Stages
  7. Soil & Growing Conditions
  8. Harvest & Storage
  9. Companion Planting
  10. Diseases
  11. Pests
  12. Kale, Sowing to Cut-and-Come-Again
  13. Plan your Kale planting
  14. Growing Kale in another region
  15. Sources
  16. Frequently Asked Questions

In Canada, kale is largely unbothered by the region's short frost-free window — it withstands frost down to around -5°C, and colder temperatures sweeten the leaves, so the usual autumn cutoff that ends most crops barely applies. Sow in spring for a summer harvest and again in mid-summer for an autumn and early-winter crop that, under snow cover or a low tunnel, often carries right through into winter.

The short answer

Ready in
50–55 days
Site
4+ hours of sun, soil pH 6–6.5
Biggest risk
Club root

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

Kale (Brassica oleracea Acephala Group)

Close-up of curly kale leaves covered in raindrops, showing the tightly ruffled leaf edges typical of curly-type kale. Photo: Ruth Hartnup, CC BY 2.0, via Wikimedia Commons.

Also known as: Leaf Cabbage, Curly Kale · 16 sources cited · Verified

Quick Facts

A bunch of freshly harvested Red Russian kale with purple stems and blue-green frilled leaves — “CSA-Red-Russian-Kale” by Evan-Amos is licensed under Public domain. Source: Wikimedia Commons
“CSA-Red-Russian-Kale” by Evan-Amos is licensed under Public domain. Source: Wikimedia Commons.
Factor Value
Soil pH 6 - 6.5
Sunlight 4-4 hours direct sun
Optimal growing temp 15-22°C
Minimum survivable temp -5°C
Time to harvest 50-55 days
Soil texture RHS: "Kale prefers rich, well-drained, firm soil, but will grow in most soil types and conditions".
Drainage RHS: well-drained, firm soil; "Kale likes sun, but will also cope in light shade". Utah State: a "sunny location".
Lifecycle biennial for most varieties, cropping until they flower in their second year; a few perennial heirloom varieties exist
Edible parts leaves
Documented problems 6 diseases, 10 pests

At a Glance

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

When to plant in Canada

Canada. Kale is the crop the Canadian season is kindest to. Clemson notes it withstands frost and that colder temperatures sweeten the leaves, so the usual Canadian constraint - a short frost-free window - barely applies: the crop is still standing and improving when frost-tender crops have finished. Sow in spring for summer picking and again in mid-summer for autumn and early winter, harvesting outer leaves cut-and-come-again from about 30 days for baby leaves or 50-70 days for mature ones. Under snow cover or a low tunnel, kale will often carry through into winter. Soil pH 6.0-6.5.

Does Kale Regrow After Cutting? (And Is It Too Late to Sow?)

Does it regrow after cutting? Yes -- that's the whole point of "cut-and-come-again" harvesting. NC State Extension confirms the method directly: "pick the big, outer leaves and let the center continue to grow." Take a few of the largest, lowest leaves at a time rather than stripping the whole plant, and it keeps producing for months.

Is it too late to sow? Kale is unusually forgiving on timing because it's genuinely hardy -- RHS records it surviving down to around -5°C, and a cold snap sweetens rather than damages the leaves. Two real windows exist, not one: sow in spring for a summer crop, or again in late summer (roughly 6 weeks before your first autumn frost) for a crop that often tastes better, since cool autumn weather is exactly what kale prefers.

Growth Stages

Stage BBCH Notes
Sowing & Establishment 0 Sow indoors from March onwards in modular trays, or outdoors March to June in shallow drills, at a PLANTING DEPTH of 1cm (RHS). Sow thinly in a seedbed 10-15cm apart and thin to the same spacing, or direct-sow three seeds every 45cm and thin to the strongest seedling per station; for cut-and-come-again salad crops, sow more thickly at roughly 7.5cm spacing (RHS). Transplant out in late spring/early summer once seedlings reach 10-15cm tall, SPACING mature plants 30-60cm apart depending on variety with a minimum of 45cm between rows (RHS). Dig in well-rotted manure or garden compost before planting; kale "prefers rich, well-drained, firm soil, but will grow in most soil types and conditions" (RHS).
Vegetative Growth & Transplanting 3 Net plants immediately after transplanting with fine-mesh insect-proof netting supported on hoops or canes to keep off cabbage caterpillars, birds/pigeons and cabbage root fly (RHS) -- young transplants are most vulnerable to root fly and flea beetle at this stage. Water regularly while plants establish so the soil does not dry out; once established, kale generally needs watering only during prolonged dry spells (RHS). Feeding "isn''t usually needed, except on poor soils or when growing in containers" -- apply a nitrogen-rich organic fertiliser if needed (RHS).
Leaf Development 7 Plants bulk up into a rosette of leaves on a thickening central stem, growing to 30-90cm tall depending on variety -- kale does not form a head, unlike cabbage. Keep netting in place and check under it regularly for cabbage caterpillars, flea-beetle peppering on young leaves, and mealy cabbage aphid colonies on the growing points, which can distort growth and make leaves inedible (RHS). Continue watering during dry spells; once well established, kale copes with dry conditions much better than most brassicas.
Harvest — Cut-and-Come-Again 8 Begin picking mature plants from September onwards, taking two or three of the lower leaves from each plant at a time (RHS); regular picking encourages more leaves to grow, and the whole rosette can also be cut to resprout. Kale is fully hardy (killing temperature around -5°C, FAO EcoCrop) and can be picked right through winter into early spring; a spell of frost is widely held to sweeten the flavour. Biennial plants bolt and flower the following spring if left in the ground -- pull and compost once cropping finishes, or, for perennial heirloom types such as ''Daubenton''s'' and ''Taunton Deane'', leave in place to keep cropping for several years (RHS).

Soil & Growing Conditions

Rows of dark-leaved black kale (cavolo nero) growing in a UK field plot — “Black kale and a new plantation on Church Lane, around the site of the Medieval Town of Wainfleet” by Chris is licensed under CC BY-SA 2.0. Source: Wikimedia Commons
“Black kale and a new plantation on Church Lane, around the site of the Medieval Town of Wainfleet” by Chris is licensed under CC BY-SA 2.0. Source: Wikimedia Commons.

Water: RHS: water seedlings and young plants regularly so the soil does not dry out; after that "plants should only need watering during prolonged dry spells". Utah State: "About 1-2 inches of water are required per week", applied "deep and infrequent".

Soil pH range

6 6.5

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

Harvest & Storage

A bunch of freshly harvested Red Russian kale with purple stems and blue-green frilled leaves — “CSA-Red-Russian-Kale” by Evan-Amos is licensed under Public domain. Source: Wikimedia Commons
“CSA-Red-Russian-Kale” by Evan-Amos is licensed under Public domain. Source: Wikimedia Commons.

When to pick: RHS: "Pick two or three of the lower leaves from each plant at a time"; for salad crops "start harvesting as soon as plants reach 10-15cm (4-6in) tall". Utah State: harvest "when the leaves reach full size".

Storage

Utah State: store at "32°F and 95% relative humidity" for "2-3 weeks". RHS states no storage method.

Companion Planting

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 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

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 Botrytis 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 --…

Diseases

severe

Plasmodiophora brassicae

RHS: resting spores "contaminate soil for up to 20 years"; causes stunted growth, purplish foliage, wilting in hot weather, massively swollen/distorted roots. Kale is Brassica oleracea, the same species as several…

Black rot
severe

Xanthomonas campestris pv. campestris

UMass CAFE: black rot (Xanthomonas campestris pv. campestris) is "most severe on broccoli, cabbage, kale and cauliflower" among the brassica crops it affects -- kale explicitly named as a principal host, not just…

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 caterpillars
high

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

Covered by the RHS phrase "All edible brassicas"; kale is Brassica oleracea Acephala Group. Most active May-October across the 5-species complex (large/small white butterflies, cabbage moth, diamond-back moth), each…

Cabbage root fly (US: cabbage maggot)
high_at_seedling_stage

Delia radicum

RHS: "Plants affected include cabbages, cauliflower, Brussels sprout and other brassicas..." -- kale is one of the RHS-named "other brassicas" grown from the same species; maggots "can kill seedling and recently…

Flea beetles
moderate

Chrysomelidae: Alticini (various spp.)

RHS Flea Beetles on Brassicas and Allied Plants page: "feed on the leaves of all brassicas and related plants... a peppering of holes particularly on salad leaves". Kale explicitly listed on RHS''s own kale grow guide…

Mealy cabbage aphid
moderate_to_severe

Brevicoryne brassicae

RHS Mealy Cabbage Aphid page: "only found on cabbages and other brassicas"; presence "can make kale inedible and affect the growth points of young brassica plants" -- kale explicitly named. Also RHS-listed under…

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…

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…

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…

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…

Plan your Kale planting

When to sow and plant Kale depends on your own frost dates. Check the Canada vegetable planting calendar, or the month-by-month guides that cover Kale: January, February, April, October, November, December. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.

Growing Kale in another region

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

Sources

The full list of 16 sources behind this guide (Clemson Cooperative Extension, EPPO Global Database, FAO EcoCrop and others) is in the references of our UK guide to kale; they describe the plant itself, which is the same wherever it grows.

Frequently Asked Questions

How long does kale take to grow?

Typically 50–55 days, depending on cultivar and growing conditions.

What soil pH does kale need?

A pH of about 6–6.5. 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 kale?

Our data links 6 diseases and 10 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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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.

Vegetable Growing Guides Canada

Last verified 2026-08-06

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