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Entire healthy mature nasturtium plant in a real garden bed, showing growth habit and scale.Primary identification image. 30–45 cm tall, 30–60 cm wide at maturity.

Nasturtium

Tropaeolum majus L.

Also called: Indian cress

Family
Tropaeolaceae
Season
Warm-season tender annual
Best grown in
Portland, Oregon

An edible, fast-growing flower that attracts black aphids and cabbage white caterpillars to itself; a classic but undocumented trap crop.

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Life cycle & growth stages

  1. 1. SeedSow large seeds 2 cm deep after frost.
  2. 2. SeedlingRound leaves in 7–12 days.
  3. 3. Mid-growthSpreading mound or trailing vine.
  4. 4. FloweringOrange, red and yellow flowers from 6 weeks.
  5. 5. SeedPods can be pickled green or dried.

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

Planting calendar for Portland, Oregon

Start indoors 2–4 weeks before last frost; transplant 1–3 weeks after last frost; direct sow 1–4 weeks after last frost; 40–60 days to maturity from sowing. 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.

NasturtiumTropaeolum majus
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
NasturtiumMar 8–Mar 22 (estimate)Apr 12–May 3 (estimate)—Apr 12–Apr 26 (estimate)May 3–May 22 (estimate)May 22–Nov 5 (estimate)
  • Start seeds indoors: Mar 8 – Mar 22
  • Transplant outdoors: Apr 12 – Apr 26
  • Direct sow: Apr 12 – May 3
  • Tend and monitor: May 3 – May 22
  • Harvest: May 22 – Nov 5

Spacing & support

In-row 25–30 cm; rows 30–45 cm. Planner footprint: 1 cell of 30 cm.

Side-profile diagram of mature nasturtium: canopy 30–45 cm tall, 30–60 cm wide, medium root zone, support and harvest-access envelope.

Soil & water

Soil
Poor to moderate, well-drained soil
pH
6–7.5
Fertility
low
Water
Moderate; tolerates dry spells.
Frost
tender; killed by frost

Support & training

No support structure needed.

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

Harvest signs

  • Flowers and young leaves any time
  • Green seed pods for pickling
Nasturtium at harvest readiness, showing the visual cues: flowers and young leaves any time; green seed pods for pickling.

Common problems

Pests: black bean aphid, cabbage white caterpillars, flea beetles

Diseases: viruses (mosaic)

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

Side-by-side: healthy nasturtium leaf or fruit and an example of viruses.

Container growing

  • Minimum 5 L (15 cm deep)
  • Use quality potting mix and water more frequently
Mature nasturtium in a correctly sized container (5 L or more) with drainage visible.

Companion overview

4 reviewed relationship records (evidence: low).

Supported or conditional

None reviewed

Avoid or separate

None with evidence

Traditional claims only: Bush beans, Cabbage, Cucumber.

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting nasturtium or other other crops in the same spot for 1 year. Rotation is about previous seasons, not about live neighbours.

Year 1Year 2Year 3TropaeolaceaeOther familyOther familyback after 1+ yearsCrop 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 nasturtium

Nasturtiums are sown directly after the last frost, flower within six weeks and keep going until frost. Bush types stay at 30 cm; trailing types run 1.5 m or more. Poor soil gives more flowers; rich soil gives leaves.

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

Nasturtiums are reliably colonised by black bean aphid and cabbage white caterpillars, which is the origin of the trap-crop tradition. The review found no controlled trial showing that this protects a nearby crop, and trap cropping requires the trap plants to be dealt with before pests move on; otherwise the nasturtium is a nursery. It is listed as a traditional claim.

Two or more mature nasturtium plants with a tape measure showing in-row spacing (25–30 cm).
Nasturtium flower detail or bolting stage.
Immature flowers of nasturtium developing on the plant.

Edible parts and safety

Edible: flowers, leaves, seed pods (pickled).

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

Pests and diseases

Common pests: black bean aphid, cabbage white caterpillars, flea beetles. Common diseases: viruses (mosaic). These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

black bean aphid on nasturtium, with a wider damage-context view.

Timeline

Season timeline for nasturtium: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Start seeds indoors Mar 8–Mar 22; Transplant outdoors Apr 12–Apr 26; Direct sow Apr 12–May 3; Tend and monitor May 3–May 22; Harvest May 22–Nov 5.

Related plants

See also: Tropaeolaceae 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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