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Entire healthy mature radish plant in a real garden bed, showing growth habit and scale.Primary identification image. 15–20 cm tall, 8–10 cm wide at maturity.

Radish

Raphanus sativus L.

Also called: Spring radish, Summer radish

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

The fastest common vegetable: sown and pulled in three to five weeks, in cool weather, with no transplanting.

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Life cycle & growth stages

  1. 1. SeedSow 1 cm deep, 2–3 cm apart.
  2. 2. SeedlingEmerges in 3–7 days.
  3. 3. ThinningThin to 3–5 cm.
  4. 4. Developing rootRoot swells from day 18.
  5. 5. Harvest readyShoulders 2–3 cm wide.
  6. 6. HarvestPull promptly; overmature roots split.

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

Planting calendar for Portland, Oregon

direct sow 4 weeks before to 4 weeks after last frost; 22–35 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.

RadishRaphanus sativus
PlantStart indoorsDirect sowAutumn sowTransplantTendHarvest
Radish—Mar 8–May 3 (estimate); May 3–Sep 30 (estimate)Sep 10–Oct 8 (estimate)——Mar 30–Nov 18 (estimate)
  • Direct sow: Mar 8 – May 3
  • Harvest: Mar 30 – Nov 18
  • Succession sow: May 3 – Sep 30
  • Autumn sowing: Sep 10 – Oct 8

Spacing & support

In-row 3–5 cm; rows 15–30 cm. Planner footprint: 1 cell of 30 cm, 16 plants per cell.

Side-profile diagram of mature radish: canopy 15–20 cm tall, 8–10 cm wide, shallow root zone, support and harvest-access envelope.

Soil & water

Soil
Loose, moist soil
pH
6–7
Fertility
low
Water
Keep evenly moist; drought makes roots hot and woody.
Frost
hardy; tolerates frost

Support & training

No support structure needed.

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

Harvest signs

  • Root shoulders 2–3 cm across at the surface
  • Pull a test radish; do not wait for size
Radish at harvest readiness, showing the visual cues: root shoulders 2–3 cm across at the surface; pull a test radish; do not wait for size.

Common problems

Pests: flea beetles, cabbage root fly

Diseases: clubroot, downy mildew

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

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

Container growing

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

Companion overview

3 reviewed relationship records (evidence: low).

Supported or conditional

Carrot

Avoid or separate

None with evidence

Traditional claims only: Cucumber.

1 popular pairing reviewed with no verified relationship.

Full companion profile

Crop rotation

Avoid planting radish 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 radish

Spring radishes mature in 22–35 days and are ideal for succession sowing every two weeks from early spring until warm weather, then again in late summer. Heat makes them pithy and hot-flavoured, and long days push them to bolt.

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

Despite their size, radishes are brassicas: flea beetles pepper the leaves, cabbage root fly maggots tunnel the roots, and they count toward brassica occupancy for rotation. Fine mesh over the row solves both insect problems.

Two or more mature radish plants with a tape measure showing in-row spacing (3–5 cm).
Radish flower detail or bolting stage.
Immature root of radish developing on the plant.

Their speed makes them useful as a marker crop sown with slow carrots or parsnips, and they can be pulled before neighbours need the space.

Edible parts and safety

Edible: root, leaves, seed pods.

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

Pests and diseases

Common pests: flea beetles, cabbage root fly. Common diseases: clubroot, downy mildew. These vary by region; a photograph is an example, not a diagnosis. See the pest and disease guides and your local extension service.

flea beetles on radish, with a wider damage-context view.

Timeline

Season timeline for radish: sowing, transplanting, flowering, harvest and bed occupancy aligned to frost dates.Text alternative: Direct sow Mar 8–May 3; Harvest Mar 30–Nov 18; Succession sow May 3–Sep 30; Autumn sowing Sep 10–Oct 8.

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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