Organic Gardening:

How to grow organic Radishes

by Frann Leach

Summer radishes are great in salads

Radishes Raphanus sativus Family: Cruciferae (Group 2)

Radishes are very versatile vegetables. As well as the small summer radishes shown which we are all familiar with as salad ingredients, there are also larger winter radishes, the Asian 'mooli' types, and also radishes grown for their leaves or pods. The large winter and mooli types are usually used cooked (although they can be peeled and chopped for use in salads, if you wish), and the pods for stir-fry or raw in salad. Young radish leaves are tender and tasty and can also be used in salads.

Site and soil

Choose an open, unshaded site with fertile, well-drained and moisture retentive soil, which should be slightly acid (min pH 5.4, but see note on clubroot - add lime if necessary to adjust pH). Brassicas have a high nitrogen requirement and also need very firm soil. To ensure sufficient nutrient levels, it is best to topdress or apply a liquid feed such as seaweed fertiiser during growth.

Because brassicas are prone to soil infections, for example, Clubroot, it's important to use a minimum 3 year rotation plan.

Cultivation

Radishes never develop well if at any stage they become overcrowded and lanky; the quality of all types is best when grown fast. In dry soil conditions, water the bottom of drills before sowing to encourage rapid germination.

Small summer radish

Make small successional sowings at 10 day intervals from late February to early September. Early sowings from February to April and late sowings in September to October may be made under cloches. Thin to about 2.5cm by 15cm (1"x6") as soon as possible. Keep well watered in dry weather at 2 gallons per sq yard per week. Midsummer sowings can be made in light shade or intersown between other crops. Harvest as required. Do not leave for too long after they reach eating size, as most varieties will become woody and unappetising, though some newer ones stand better than earlier varieties.

Mooli and large winter radishes

Used in salads, stir-fries, stew and especially curry. These midsummer-sown radish prefer a site in light shade, or can be intersown between other, taller crops. Soil should be light, well drained and fertile; rich sandy soils are ideal. Sow seeds 1cm (½") deep in mid June to August (bolt resistant cultivars can be sown in mid May). Spacing should be about 15cm each way (6"x6") after thinning. Do not allow seedlings to become overcrowded at any stage. Make sure they are kept well weeded and watered in dry weather at 2 gallons per sq yard per week to prevent woodiness. Mooli and winter radishes mature in 2½-3 months. Winter types can be left in the ground during winter and lifted when required, or lifted and stored in boxes in a cool shed or clamps, after trimming off the leaves. Mooli store well in the freezer if sliced and blanched.

Leaf radish

Although most cultivars can probably be sown closely for the use of the leaves, some have been selected especially. For a very early crop, sow seeds under cover in an unheated greenhouse, frame or polytunnel in February or March. Follow with outdoor sowings as soon as the soil is workable through till May and June. Sow again outdoors in late August or September or under cover in late September or October for a winter crop. Midsummer sowings are likely to bolt prematurely. Seeds can be broadcast for seedling crops. Spacing is 25cm (10") each way for large plants. Plants can be cut at 5-8cm (2-3") high as a seedling crop for salads or left to reach about 8" and cooked as greens. If they are thinned a few mooli-type radishes will develop.

Pod radish

Almost all radishes will eventually run to seed and produce pods, but at least one variety has been especially bred to produce them. Sow March to August thinly 1cm (½") deep in rows 30cm (12") apart, thin to 30cm (12") between plants. Harvest pods from June to November before the seeds start to swell.

Note on clubroot Soil may remain infected for 20 years; steps to avoid introduction include: good drainage rotation liming acid soils to a pH around 7 working in high levels of organic matter ensuring clean plants are used - source must be known to be free of disease (best grown at home in sterile medium) boots and tools used on infected land must be thoroughly cleaned before use on clean land Once infected avoid growing any brassicas except fast maturing types such as Texsel greens or cut and come again oriental seedlings. If you have no other land available, and you must grow types with a lengthy growing season, you can try sowing seed in modules, and potting up until the plants reach a height of 10cm (4") before planting out. A root drench may also help.

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