Radishes

Radishes (*Raphanus sativus*) are compact, quick-growing members of the brassica family. Salad types can be ready only four weeks after germination, making them useful for small gardens, containers, gap filling and marking rows of slow-germinating crops. Small repeat sowings provide a steady supply of crisp, peppery roots rather than one large glut.

They are cool-season plants and usually grow best in spring and late summer. Heat, drought and overcrowding can prevent roots swelling or trigger premature flowering. Beyond familiar red salad roots, the crop includes larger winter radishes, long oriental or daikon roots and edible-podded forms grown for crisp immature seed pods.

Sow directly where plants are to grow. Germination normally takes seven to ten days and salad crops need little ground for long. The main requirements are fine, stone-free soil, adequate spacing and consistently moist conditions that sustain uninterrupted growth.

Salad radishes are small, fast spring and summer crops eaten raw. They occur as globes or cylindrical roots in red, pink, purple, white, yellow and black. Winter radishes are larger and slower, sown in late summer for cool-season harvest; both roots and leaves are edible. Oriental radishes, also called daikon or mooli, usually form long mild white roots and need at least eight weeks. Edible-podded radishes produce tall flowering stems and plentiful spicy pods, particularly in warm weather.

Choose according to season, available soil depth, colour, heat and kitchen use. AGM cultivars have shown reliable garden performance. Do not sow winter types too early because they may bolt before forming useful roots.

Recommended varieties

Radish ‘Longipinnatus’

An oriental mooli with a firm white tapering root reaching 30cm or more. Harvest in autumn and early winter for eating raw or cooked.

Cultivar sourceAllotment Pro variety guide

Radish ‘Scarlet Globe’ AGM

A quick-maturing salad cultivar producing round scarlet-red roots with white flesh. Roots are pleasantly mild when harvested young.

Cultivar sourceAllotment Pro variety guide

Radish ‘Black Spanish Round’

A winter radish with striking black skin and sharp-flavoured white flesh. Sow in July or August for harvesting through winter.

Cultivar sourceAllotment Pro variety guide

Radish ‘French Breakfast 4 Francis’ AGM

A salad cultivar with cylindrical red roots ending in a white tip. Its crunchy white flesh has a mild peppery flavour.

Cultivar sourceAllotment Pro variety guide

Radish ‘Amethyst’ AGM

An attractive salad radish with purple skin and crisp white, tangy flesh. The roots are slow to become woody.

Cultivar sourceAllotment Pro variety guide

Radish ‘China Rose’

A medium-to-large oblong winter radish, synonymous with ‘Rose d’Hiver de Chine’, valued for tasty roots and cool-season cropping.

Cultivar sourceAllotment Pro variety guide

Choose an open, sunny position. Light shade is useful for salad radishes in midsummer, keeping soil cooler and reducing drought stress. Long winter and oriental cultivars need deep ground because some roots exceed 30cm. Avoid compacted or stony sites that distort long roots.

Remove weeds, fork through the soil to break hard lumps and compaction, take out stones and rake the surface to a fine texture. Radishes do not require heavily manured ground. In a no-dig bed, apply a settled organic mulch and sow into its fine surface.

For short-rooted salad radishes, use a container at least 30cm wide and deep, filled with peat-free multipurpose compost. Ensure free drainage and position it where watering is convenient, because containers and young seedlings dry rapidly.

Sow salad radishes in spring, early summer and late summer, avoiding the hottest, driest periods. Make drills 1cm deep, place seeds 2.5–5cm apart and leave 15cm between rows. Sow a short row every few weeks. For an early crop, begin in February in soil pre-warmed and protected by cloches.

Sow winter radishes in July or August about 2cm deep. Space or thin seedlings to 15–20cm, with rows 15cm apart. Sow oriental radishes during spring and summer in a similar way, allowing the same generous spacing for their large roots. Sow edible-podded types 1cm deep and 10cm apart in spring or summer.

If seed falls too thickly, remove smaller seedlings promptly. Salad radishes need at least 2.5cm between plants; winter and oriental roots need at least 15cm. Crowded leafy tops cannot gather enough light and water to swell good roots.

Use fast salad radishes between slower crops such as peas and potatoes, or as row markers for parsnips and onions. They emerge first and should be harvested before competing with the main crop.

Keep soil consistently moist so roots develop rapidly, evenly and without splitting. Water during dry weather before plants wilt. Drought may stop roots swelling, while alternating dry and wet conditions encourages splitting. Container crops and seedlings require especially frequent checks.

Spring salad crops often outperform summer sowings because conditions are mild and rainfall more dependable. In warm weather, use light shade away from midday sun and maintain steady moisture. Pull any ordinary root cultivar that begins producing a flower stem, unless it is intentionally being grown for edible pods.

Weed regularly because radishes dislike competition. Hoe carefully between rows but hand-weed close to plants to avoid cutting or scarring the roots. Feeding is generally unnecessary in reasonably fertile soil; excessive richness can promote leaves at the expense of roots.

Harvest salad radishes young, commonly four to six weeks after germination, when roots are about 2.5cm across. Very early protected sowings may take six to eight weeks. Pull only what is needed and eat promptly. Roots left too long become woody, pithy, excessively hot and eventually inedible.

Oriental radishes mature more slowly, taking at least eight weeks. Lift their long tapering roots in late summer and autumn, loosening surrounding soil first to prevent breakage. They may reach 30cm or more and remain mild without quickly turning woody. Eat them raw, grate into salads or cook like winter radish.

Edible-podded forms should be picked repeatedly while the long pointed pods are young, crisp and tender. Older pods become fibrous. Regular harvesting encourages more flowers and pods; remove any that become over-ripe.

Winter radishes can remain in the ground and be lifted as needed through winter. Protect roots with cloches, biodegradable fleece or cardboard during freezing weather. Alternatively, lift the crop in November and keep it in a refrigerator or similarly cool place.

These larger roots remain crisp and resist woodiness even at useful size. Scrub, slice or grate them raw, or add them to stews and stir-fries like turnips. Their peppery leaves are edible too, used raw while tender or cooked similarly to chard.

Handle stored roots carefully and remove damaged foliage without cutting into the crown. Check periodically and use any root that softens. Do not attempt to store small salad radishes for long; their best texture comes directly from the soil.

Roots fail to swell where plants are hot, dry or overcrowded. Provide correct spacing, sow salad types mainly in mild weather and water consistently. Premature flowering also follows stress or unsuitable day length. Woody, bitter or excessively spicy roots are normally over-mature, so harvest salad radishes promptly at about 2.5cm diameter. Uneven moisture causes splitting, although split roots are often still edible.

Slugs and snails attack seedlings in damp conditions. Cabbage root fly larvae tunnel into roots, especially slower winter and oriental crops; protect sowings with biodegradable fleece or insect-proof mesh. Flea beetles pepper leaves with small holes, usually cosmetic on a vigorous crop. Brassica downy mildew affects foliage, while club root distorts roots in contaminated acidic ground.

Common problems