How to Grow Kale in the USA
On this page
- Kale (Brassica oleracea Acephala Group)
- Quick Facts
- At a Glance
- When to plant in the USA
- Does Kale Regrow After Cutting? (And Is It Too Late t...
- Growth Stages
- Soil & Growing Conditions
- Harvest & Storage
- Companion Planting
- Diseases
- Pests
- Kale, Sowing to Cut-and-Come-Again
- Plan your Kale planting
- Growing Kale in another region
- Sources
- Frequently Asked Questions
In the US, kale isn't timed to the frost date the way most vegetables are — Clemson Extension notes it shrugs off frost, with a killing temperature of around 23°F (-5°C), and colder weather actually sweetens the leaves. Because of that, growers sow in spring for a summer crop and again in late summer for the autumn-and-winter crop, which tends to taste even better.
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)
Also known as: Leaf Cabbage, Curly Kale · 16 sources cited · Verified
Quick Facts
At a Glance
When to plant in the USA
United States. Kale is not timed against the frost date, because frost is not the enemy - Clemson records that it withstands frost and that colder temperatures actively sweeten the leaves. That frees it from the spring window most crops are squeezed into: sow in spring for a summer crop, and again in late summer for the autumn and winter crop that will be the better-tasting of the two. Pick immature leaves from about 30 days after sowing, or let plants reach maturity at 50-70 days and harvest cut-and-come-again, taking the outer leaves and leaving the growing point. Soil pH 6.0-6.5. The one real limit is heat rather than cold, which is why the autumn sowing outperforms the spring one across most of the country.
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 23°F (-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 23°F (-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
Harvest & Storage
Companion Planting
Diseases
Pests
Kale, Sowing to Cut-and-Come-Again
Plan your Kale planting
When to sow and plant Kale depends on your own frost dates. Check the USA vegetable planting calendar, or the month-by-month guides that cover Kale: January, March, July, 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
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Black rot shows yellow V-shaped lesions with the point of the V directed toward a vein, favoured by high temperature and humidity, surviving on debris up to two years when buried plus on wild mustard and contaminated seed; avoid cole crops where it occurred within two to three years and do not handle wet plants. Downy mildew is grey mould on the lower leaf surface with yellowing above. Alternaria leaf spot makes brown circular target spots with concentric rings between 60 and 90°F, overwintering on residue, calling for three-year rotation. Pythium damping-off rots seedlings at the soil line.
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Diamondback moth is "the most serious insect pest of brassica crops in South Carolina", leaving a window-pane appearance where the upper leaf surface stays intact. Damage is quantified relative to each other: one cabbage looper does roughly the damage of 5 diamondback moth larvae, and imported cabbageworm about two-thirds of a looper. Cross-striped cabbageworm hatches in masses and can rapidly skeletonise a plant, dropping to pupate just under the soil surface. Cabbage webworm damages buds and growing points, causing lateral budding. Cabbage aphids are commoner in cool autumn weather. Flea beetles are most problematic on mustard and turnips, which lack the protective waxy coating.
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US extension corroboration: black rot (Xanthomonas campestris pv. campestris) affects all cultivated brassicas; "most severe on broccoli, cabbage, kale and cauliflower".
These 7 sources are specific to this region. 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
Almost everything on this page resolves to your own frost dates rather than the calendar — the last spring frost moves by roughly two months between zone 3 and zone 10. The USA Garden Planner works from your zone so the timing is already decided before the season starts.
Get the USA Garden Planner →Instant PDF download · Written for US growing conditions
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 USDA hardiness-zone and frost-date data, with Cooperative 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.
Related Problem Guides
Last verified 2026-08-06
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