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Entire healthy mature broccoli plant in a real garden bed, showing growth habit and scale.Primary identification image. 45–75 cm tall, 45–60 cm wide at maturity.

Broccoli

Brassica oleracea var. italica Plenck

Also called: Calabrese, Sprouting broccoli

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

A cool-season brassica grown for its immature flower heads; spring and autumn crops avoid the heat that opens heads prematurely.

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Life cycle & growth stages

  1. 1. SeedSow indoors 6–8 weeks before last frost.
  2. 2. SeedlingEmerges in 5–10 days.
  3. 3. TransplantSet out 2–3 weeks before last frost.
  4. 4. Mid-growthLeafy plant 45–60 cm wide.
  5. 5. Head formingCentral head develops over 2–3 weeks.
  6. 6. Harvest readyTight buds, 10–20 cm head.
  7. 7. HarvestCut with 15 cm stem; side shoots follow.

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

Planting calendar for Portland, Oregon

Start indoors 6–8 weeks before last frost; transplant 0–3 weeks before last frost; 55–80 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.

BroccoliBrassica oleracea var. italica
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
BroccoliFeb 8–Feb 22 (estimate)—Jul 30–Aug 13 (estimate)Mar 15–Apr 5 (estimate)Apr 5–May 9 (estimate)May 9–Jul 22 (estimate)
  • Start seeds indoors: Feb 8 – Feb 22
  • Transplant outdoors: Mar 15 – Apr 5
  • Tend and monitor: Apr 5 – May 9
  • Harvest: May 9 – Jul 22
  • Autumn sowing: Jul 30 – Aug 13

Spacing & support

In-row 45–45 cm; rows 60–90 cm. Planner footprint: 2 cells of 30 cm.

Side-profile diagram of mature broccoli: canopy 45–75 cm tall, 45–60 cm wide, medium root zone, support and harvest-access envelope.

Soil & water

Soil
Fertile, moisture-retentive loam
pH
6–7
Fertility
high
Water
Steady water during head formation.
Frost
hardy; tolerates frost

Support & training

No support structure needed.

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

Harvest signs

  • Head 10–20 cm across with tight, dark buds
  • Cut before any bud shows yellow
  • Side shoots follow for weeks
Broccoli at harvest readiness, showing the visual cues: head 10–20 cm across with tight, dark buds; cut before any bud shows yellow.

Common problems

Pests: cabbage white caterpillars, cabbage aphid, cabbage root fly, flea beetles

Diseases: clubroot, downy mildew, black rot

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

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

Container growing

  • Minimum 20 L (30 cm deep)
  • Use quality potting mix and water more frequently
Mature broccoli in a correctly sized container (20 L or more) with drainage visible.

Companion overview

3 reviewed relationship records (evidence: medium).

Supported or conditional

Sweet alyssum, White clover

Avoid or separate

None with evidence

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting broccoli 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 broccoli

Calabrese broccoli is transplanted 2–3 weeks before the last frost and harvested 55–80 days later, followed by smaller side shoots for several weeks. Heads bolt into yellow flowers in heat, so time spring crops to finish before midsummer and plant again in late summer.

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

Broccoli is the crop in which sweet alyssum strip intercropping has been studied for aphid biocontrol: alyssum supports hoverflies whose larvae eat aphids, and the agronomy work shows the benefit depends on the share of the bed given to alyssum and its distance from the crop.

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

Pests and diseases match cabbage; mesh cover and a three-year brassica rotation are the main defences.

Edible parts and safety

Edible: flower buds, stems, leaves.

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

Pests and diseases

Common pests: cabbage white caterpillars, cabbage aphid, cabbage root fly, flea beetles. Common diseases: clubroot, downy mildew, black rot. 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 broccoli, with a wider damage-context view.

Timeline

Season timeline for broccoli: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Start seeds indoors Feb 8–Feb 22; Transplant outdoors Mar 15–Apr 5; Tend and monitor Apr 5–May 9; Harvest May 9–Jul 22; Autumn sowing Jul 30–Aug 13.

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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