Radish

Sowing: Radish is a cool-season crop that is direct-sown rather than transplanted, since disturbing the root affects its development. Seeds are sown about 1/4 to 1/2 inch deep and later thinned to a few inches apart, with new sowings made every one to two weeks to keep a continuous supply coming as earlier plantings mature.

Siting and water: It grows best in full sun to part shade, in loose, well-drained soil rich in organic matter, and needs consistent, even moisture to keep the roots tender and well flavoured; light, sandy soils need more frequent watering than heavier ones. Radish can be sown alongside slower-germinating crops such as carrots or parsnips, since its quick emergence helps break the soil crust for them, and it also works as a fast intercrop between rows of slower vegetables.

Feeding and rotation: Applying nitrogen fertiliser or fresh manure close to planting tends to push leafy top growth at the expense of the root, so it is best avoided. Because radish belongs to the same family as cabbage and other cole crops, it should not be grown in the same ground more often than once every three or four years, to reduce the buildup of shared soil-borne diseases.

Radish is attacked by several insect pests, including cabbage root maggots, flea beetles, whiteflies, aphids, mites, caterpillars, and nematodes; swede midge can attack the leaves and cause crinkling and distortion. Clubroot is a significant soil-borne disease, managed by raising soil pH with lime, and root rot can also occur.

Hot weather, over-mature roots, or bolting cause the root to turn woody, pithy, and more bitter, so timely harvest and cool growing conditions help avoid this. The plant can also cause contact dermatitis in some people.

Radish is ready to harvest quickly, often within three to six weeks, once the shoulders of the root begin to show at the soil surface; larger and winter types take longer to mature. Small roots are pulled by hand, while larger types are loosened with a spade or fork before pulling, and roots should not be left in the ground too long or they become tough and bitter.

After harvest, small radishes keep for about one to two weeks refrigerated, while larger, dense-fleshed types can be stored for up to about two months.

Culinary: The root is the main edible part, eaten raw, cooked, or pickled, and used fresh as a salad vegetable and garnish; the young leaves are edible, especially when cooked, the flowers have a spicy flavour and are used raw in salads, and the seeds are sprouted and eaten as sprouts. In parts of Asia, radish is a staple food prepared fresh, pickled, dried, and cooked in a wide range of dishes.

Forage and cover crop: Radish is also grown for livestock forage, producing digestible above-ground biomass suitable for grazing, and as a cover crop, where its deep taproot can help relieve soil compaction, take up nitrogen left by a previous crop, and suppress weeds and some soil pests. Its seeds are high in oil, which has been tested as a source of biodiesel.

Medicinal: In various parts of the world, the leaves and roots have historically been used in traditional preparations associated with treating cancer and as antimicrobial and antiviral remedies.

Radish originates from the Mediterranean region and has been in cultivation for thousands of years, spreading over that time to be grown across the world in many distinct forms.