Why Grow it?
Try eating a raw radish with a bit of butter and some seasoning and you have all the reasons you need to grow them. Crunchy, peppery and delicious. They are tremendously easy to grow and mature quickly so there's a very quick return – ideal, therefore, if you are just starting out. Don't dismiss them as a one-trick veg, though – there are dozens of varieties, including turnip-sized winter radishes that can be stored over the winter. The French Breakfast radish is my favourite – I like it grated into salads to give a little peppery zing.
They can be sown pretty much anywhere – often thrown in among other veg and even in partial shade. Always sow directly in the soil – they don't fare well when transplanted from seed trays. Sow a small number of seeds regularly (every two to three weeks) from April on. Sow thinly 1cm deep and 3cm apart.
Water regularly in dry weather but don't over-water as it will encourage too much leafy growth.
They will be ready to eat within a month, which is one of the fastest of all vegetables. Don't let them get too big as they become overly peppery and tend towards tasting "woody" when too large.
GIY recommended varieties
Cherry Bell; French Breakfast
Slugs can nibble at radishes but they are rarely so badly eaten as to be inedible. Otherwise, radishes are pretty much trouble-free.
* Fast-growing radishes are often sown between rows of slower-growing vegetables as they can be harvested without upsetting the other veg. They are a brassica, however, so ideally you should keep them in the brassica group in your rotation plan.
* Radish tops can be used in soups.