Root crop · reference page

Radishes

A quick direct-sown root crop for small repeated batches in cool, evenly moist conditions.

Scientific name: Raphanus sativus

Editorial guidance without independent agronomic review

Published: 2 August 2026 · Updated: 2 August 2026

Direct sun reference
3 h
Usable root depth
18 cm
First-harvest band
25–55 days

Getting started

Sowing and space

Direct-sow thinly into the final loose soil or compost and thin promptly.

Allow about 18 cm of usable depth and roughly 6 cm between plants.

Watering reference: moderate and regular. Adjust to rain, heat, wind, growth stage and container volume.

Planting windows by broad profile

These original editorial windows compare thermal groups, not live weather. Check current frost, heat, rainfall and packet directions.

Mild south-west and coast

Check the actual last frost, soil drainage, salt exposure and wind shelter; a protected coastal plot can differ sharply from a nearby inland hollow.

FebMarAprMayJunJulAugSep

Southern lowland

Do not treat a regional average as a frost date. Check the current forecast, water restrictions and the temperature of the actual soil or container.

FebMarAprMayJunJulAugSep

Avoid relying on the hottest dry weeks for tender roots.

Drier eastern lowland

Plan for water conservation and cold-air pockets; a dry spring can delay germination even when daytime temperatures look suitable.

MarAprMayJunJulAugSep

A short dry spell can make shallow rows harsh and uneven.

Wet western maritime

Prioritise drainage, shelter and safe support. A broad wet profile is not a reason to skip checking the root zone before watering.

MarAprMayJunJulAug

Cool northern lowland

Use local frost observations and an early cultivar as separate pieces of evidence; neither guarantees that a tender crop will finish outdoors.

MarAprMayJunJulAug

Upland, short season

Confirm soil warmth, exposure and the remaining frost-free period at the plot. Covers must be secure, ventilated and removed when unsafe.

AprMayJunJul

Northern island and coast

Choose shelter without blocking access or drainage, and compare the plot with current local forecasts rather than a mainland monthly average.

AprMayJunJulAug

Shelter young leaves from strong wind without trapping moisture.

Practical care

  • Sow a short row at a time.
  • Harvest before roots become coarse or split.

Points to check

  • Crowding and dryness reduce root quality.
  • Do not leave mature roots waiting for a later harvest.

Provenance and confidence

This rule is an original editorial synthesis and no independent local agronomic review is claimed.

  • United Kingdom home food garden editorial synthesis — version 1

    Global Garden Planner

    Original seven-profile model, planting bands and en-GB corpus. It remains an editorial draft until an independent UK agronomic review is recorded.

    Editorial role: internal synthesis · Rights position: Original project content · Accessed: 2 August 2026

    Open source

  • UK regional climates

    Met Office

    Supports broad east–west, north–south, maritime and topographic context. The project profiles and month bands are original and are not a transformation of Met Office regions or data.

    Editorial role: fact reference · Rights position: Website information linked and paraphrased under the applicable Met Office terms; no map, table, dataset or service is redistributed · Accessed: 2 August 2026

    Open source

  • Positioning vegetables

    Royal Horticultural Society

    Supports observing sun, shade, shelter and competition at the final growing position.

    Editorial role: fact reference · Rights position: Copyright source used only as a linked factual reference; no RHS text, image, planner or calendar is reproduced or adapted · Accessed: 2 August 2026

    Open source

  • Planning a vegetable garden

    Royal Horticultural Society

    Supports considering soil, cultivar and available space. It is not used to create the package calendar bands.

    Editorial role: fact reference · Rights position: Copyright source used only as a linked factual reference; the RHS vegetable planner and calendars are expressly excluded from reuse · Accessed: 2 August 2026

    Open source

Use it in context

A month alone cannot resolve cultivar, soil, microclimate or a current extreme.

Use reputable planting material. Use clearly labelled seed or healthy young plants from a traceable supplier and check current plant-health rules, including the distinct arrangements for Great Britain and Northern Ireland, before ordering or moving material.

If a plant protection product is considered at all, check the current GB or Northern Ireland authorisation for the crop and use, then follow the complete label; the project does not prescribe a treatment.