Garden PlannerEvidence-aware. Garden with confidence.
Entire healthy mature kale plant in a real garden bed, showing growth habit and scale.Primary identification image. 45–90 cm tall, 45–60 cm wide at maturity.

Kale

Brassica oleracea var. sabellica L.

Also called: Curly kale, Lacinato, Cavolo nero, Borecole

Family
Brassicaceae
Season
Cool-season biennial grown as an annual
Best grown in
Portland, Oregon

The hardiest brassica: a long-standing leaf crop that improves after frost and can be picked for months.

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Life cycle & growth stages

  1. 1. SeedSow indoors or direct.
  2. 2. SeedlingEmerges in 5–8 days.
  3. 3. TransplantSet out 40–45 cm apart.
  4. 4. Mid-growthUpright rosette 45–60 cm.
  5. 5. Harvest readyLeaves hand-sized.
  6. 6. HarvestPick lower leaves; leave the crown.
  7. 7. OverwinteringStands through frost; flowers in spring.

Growth stages are ordered chronologically; timing varies with cultivar, temperature, light and care.

Planting calendar for Portland, Oregon

Start indoors 4–6 weeks before last frost; transplant 0–4 weeks before last frost; direct sow 2 weeks before to 4 weeks after last frost; 50–65 days to maturity from transplant. Windows are derived from the region's average frost dates (last Apr 5, first Nov 5) and are estimates until you confirm your own dates in the calendar.

KaleBrassica oleracea var. sabellica
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
KaleFeb 22–Mar 8 (estimate)Mar 22–May 3 (estimate)Aug 13–Sep 10 (estimate)Mar 8–Apr 5 (estimate)—Apr 27–Sep 29 (estimate)
  • Start seeds indoors: Feb 22 – Mar 8
  • Transplant outdoors: Mar 8 – Apr 5
  • Direct sow: Mar 22 – May 3
  • Harvest: Apr 27 – Sep 29
  • Autumn sowing: Aug 13 – Sep 10

Spacing & support

In-row 40–45 cm; rows 45–60 cm. Planner footprint: 2 cells of 30 cm.

Side-profile diagram of mature kale: canopy 45–90 cm tall, 45–60 cm wide, medium root zone, support and harvest-access envelope.

Soil & water

Soil
Fertile loam
pH
6–7.5
Fertility
high
Water
Regular water in summer; little needed in cool months.
Frost
very hardy; tolerates frost

Support & training

No support structure needed.

Kale mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Harvest signs

  • Leaves hand-sized
  • Pick lowest leaves first
  • Sweeter after frost
Kale at harvest readiness, showing the visual cues: leaves hand-sized; pick lowest leaves first.

Common problems

Pests: cabbage white caterpillars, cabbage aphid, flea beetles, whitefly

Diseases: clubroot, leaf spot

Appearance alone is not a diagnosis; confirm with a regional extension guide.

Side-by-side: healthy kale leaf or fruit and an example of clubroot.

Container growing

  • Minimum 15 L (25 cm deep)
  • Use quality potting mix and water more frequently
Mature kale in a correctly sized container (15 L or more) with drainage visible.

Companion overview

2 reviewed relationship records (evidence: low).

Supported or conditional

Sweet alyssum

Avoid or separate

None with evidence

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting kale or other cabbage family crops in the same spot for 3 years. Rotation is about previous seasons, not about live neighbours.

Year 1Year 2Year 3BrassicaceaeOther familyOther familyback after 3+ years

Shared risks in Brassicaceae: clubroot, cabbage root fly, cabbage white caterpillars.

Crop rotation hub

Sources, reviewer & update

Sources

Reviewer: Garden Planner editorial team (pending independent horticultural review)

Last reviewed: August 15, 2026 · version 1

Found an error or have feedback? Let us know.

Growing kale

Kale can be transplanted in spring or sown directly, but its real season is autumn and winter; plants set out in midsummer stand through frost and, in mild climates, until spring. Summer leaves are tougher and more attractive to caterpillars.

Kale seed beside a ruler or coin for scale.
Kale seedling at cotyledon and first-true-leaf stage, in soil, distinguishable from common weeds.
Kale mid-season before harvest, showing branching, vining, rosette or upright habit and space occupied.

Pick lower leaves from the outside, leaving the growing tip, and a single plant crops for months. Mature plants reach 45–90 cm and cast light shade.

Two or more mature kale plants with a tape measure showing in-row spacing (40–45 cm).
Kale flower detail or bolting stage.
Immature leaves of kale developing on the plant.

Cabbage whites, aphids and flea beetles are routine; mesh cover is the practical answer. Kale counts as a brassica for clubroot rotation.

Edible parts and safety

Edible: leaves.

Hands or tool harvesting kale correctly (cut, pull, twist or pick) without damaging the plant.

Pests and diseases

Common pests: cabbage white caterpillars, cabbage aphid, flea beetles, whitefly. Common diseases: clubroot, leaf spot. These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

cabbage white caterpillars on kale, with a wider damage-context view.

Timeline

Season timeline for kale: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Start seeds indoors Feb 22–Mar 8; Transplant outdoors Mar 8–Apr 5; Direct sow Mar 22–May 3; Harvest Apr 27–Sep 29; Autumn sowing Aug 13–Sep 10.

Related plants

See also: Brassicaceae family page · crop rotation · regional calendar · guides

Our Methodology & Sources

We synthesize peer-reviewed research, university extension publications, and trusted horticulture resources. Our evidence levels help you understand how strong the science is behind the guidance.

Evidence tiers

Supported evidenceConsistent results from multiple robust studies
Traditional claimHistorical use reported, limited scientific support
Context dependentMixed or variable results across conditions
No verified relationshipNo reliable evidence identified

Primary source types

  • Peer-reviewed journal articles
  • University extension publications
  • Government & research institute reports
  • Systematic reviews & meta-analyses

Last updated

August 24, 2026

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