Radish, Daikon 'Watermelon Radish'

The colourful 'Watermelon Radish' of historic China is a winter radish that is related to the Daikon. Sweeter than most radish varieties, they have a beautiful interior that looks like a ripe watermelon. They have a mild sweet taste and crisp texture and are great for eating fresh, salads, pickling, or as a beautiful garnish.

The Watermelon radish produces 10cm (4in) round roots with white and green skin, but the magic is in their bright-magenta interior which is sweet, crisp, and delicious. Occasionally, these radish even have a purple colour and a darker interior.
Beautiful and unique, these winter radishes are best grown in a sunny location in cool conditions and perfect for autumn and winter sowing. Depending on where you live, you can even grow this radish in winter if the weather is mild enough, they will tolerate temperatures down to around -3°C. The flesh is firm, succulent and tender with a crisp snap like consistency, and the taste is subtle, sweet and mildly peppery. Cooler climates produce radishes with a less spicy flavour.

Seeds can be sown year round, they are an excellent variety for home gardeners and market growers. They are unbelievably fast-growing even in the cool, shortening days of autumn and are an excellent root vegetable for the winter kitchen. Sow directly where they are to grow in a warm, sunny location, the large wide roots will need space to grow, so thin to one plant every 10cm. Sow a small crop every two weeks to guarantee a continuous harvest. About 45 to 55 days from planting to harvest.
The roots store very well. Typically producing radishes ranging in size between the from a golf ball to a tennis ball, and averaging 5 to 10cm (2 to 4in) in diameter, with a round to oval appearance and a single taproot extending from the root’s base.

The Watermelon Radish, also known as Red Meat Radish is a staple of Japanese and Korean cuisine, they have a mild taste that is excellent for oriental dishes and can be used wherever a recipe calls for Daikon radish. The leaves are also prepared cooked or pickled. When cut, the bright pink and white flesh makes a beautiful accent for any salad. The roots can be grated with a little sesame oil or soy sauce to make a tasty garnish, or simply thinly slice and serve with a squeeze of fresh lime and a pinch of salt and pepper, or sugar. They are also good for pickling.

Prepare the site:
Radishes prefer regular garden soil, Soil should be worked to a depth of at least 20cm (8in) to keep the roots nice and straight, smooth, etc. Do not use raw or fresh manure on this crop or it will quickly bolt to seed. Smaller growers should consider raised beds. Radishes can handle a little shade, especially if the temperatures are creeping up, but they need several hours of direct sun to fully develop.

Sowing:
Sow seeds direct in late spring through summer after last frost in a warm, sunny location. Sown from mid June to mid July, it can be harvested during cooler weather during late August or September. Seed germinates in 5 to 7 days at 4 to 21°C (40 to 70°F). Make successive plantings, at least three sowings a few days apart.
Sow outdoors in a sunken drill 2 to 2.5cm (1in) deep, in rows 25cm (9in) apart in rows 45 to 60cm (18 to 24in) apart. Fill in the soil round the stem as the seedling grows. Daikon types tend to grow up out of the ground as they mature, this causes the development of green shoulders. At each cultivation, push the soil over the top of the root to keep them white.
Keep moist and thin to 15 to 20cm (6 to 8in) apart. Proper thinning focuses the harvest and avoids disappointing stragglers that have taken too long to develop. Slow development makes radishes hot in taste and woody in texture.

Cultivation:
If you want good-tasting radishes also pay close attention to the watering regimen you provide. Moisture stress can result in the same woody, hot radishes that poor soil conditioning and lack of fertiliser or humus will result in.
This type does best on loose ground (like carrots) so you must be careful not to compact sandy soils too much by walking down between the rows.
Daikon radishes are frost-tolerant, with some varieties able to tolerate temperatures down to around -3°C. In such temperatures, the outer leaves may die back, but as long as there are still green leaves, the plant is still alive.

Harvesting: 45 to 55 days
Plants will be ready to harvest when they are of usable size and relatively young from 21 days, starting when roots are less than 1 inch in diameter.
Radishes remain in edible condition for only a short time before they become pithy (spongy) and hot.
In dry weather the bed should be watered the day before they are pulled. Gently hold the tops twist and lift. Remove the tops by twisting them off with your hands. The tops are very tasty and can be cooked and eaten like spinach.

Storage:
Save the young thinnings of both summer and winter radishes. They are delicious with tops and bottoms intact. Both summer and winter radishes store well in the refrigerator once the tops have been removed. The radish leaves cause moisture and nutrient loss during storage.
Fresh leaves of daikon can also be eaten as a leaf vegetable, they are often removed when sold in a store because they do not adjust well to the refrigerator, yellowing quite easily.
Store greens separately for 2 to 3 days. Refrigerate radishes wrapped in plastic bags for 5 to 7 days. Store roots in dry sand, soil, or peat for winter use.

Culinary Use:
As with any Brassica member, mustard oils are responsible for the tangy taste of radishes. All varieties are excellent sources of Vitamin C and, ounce for ounce, have about 42% as much as fresh oranges.
Just like carrot tops, radish greens can be used in a variety of dishes, including raw in blended drinks or in salads. Radishes are high in Vitamin C, folate and potassium. They are known to relieve indigestion and flatulence, as well as being a good expectorant.

Origin:
The radish is an anciently annual or biennial cultivated vegetable. It most likely originated in the area between the Mediterranean and the Caspian Sea. It may come from the wild radish in southwest China. It is possible that radishes were domesticated in both Asia and Europe.
The early domestication of radishes can be traced back to around about 4000 years ago. According to Herodotus (484-424 BC), radish was one of the important crops in ancient Egypt, as radish was depicted on the walls of the Pyramids. Cultivated radish and its uses were reported in China nearly 2000 years ago and in Japan, radishes were known some 1000 years ago.
Evolutionary processes and human selection of preferred types have led to significant variations in size, colour and taste. Among them, small-rooted radishes are grown in temperate regions of the world and harvested throughout the year. Larger-rooted cultivars such as Chinese radish are predominant in East and Southeast Asia.
Watermelon radishes roots may have green shoulders, indicating the presence of chlorophyll due to exposure to sunlight. Underneath the surface, the flesh has a ring of white just below the skin, transitioning to bright pink, fuchsia, or a deep magenta pink centre. The pink colour is due to the presence of anthocyanin pigment.

Nomenclature:
The genus name raphanus, from the Latin raphanus (also raphanos meaning ‘radish’), derives from Ancient Greek ῥάφανος (raphanos), ῥαφανίς (raphanis) which means ‘easily reared.’ See also rháphys or rhápys meaning ‘turnip’.
The species name sativus is taken from the Latin sativus meaning 'sown" or 'that which is sown', meaning cultivated. It is found in the binomial names of many domesticated plant species - sativus (masculine), sativum (neuter), or sativa (feminine).
The common name radish is from Middle English radiche, from Old English rædic, (compare Old French radise or radice), derived from Latin rādīx, or rādīc meaning 'root'
The word Daikon in Japanese means 'great root.' Daikon sprouts, known as kaiware, are a popular garnish for salads and sushi.
The Chinese word for these radishes is ShinRi-Mei, meaning 'beauty in the heart.', Mantanghong, Beauty Heart, Xin Li Mei.
Commonly called Watermelon radish, due to its colouring on the inside, it is also called the 'red meat' radish, but thankfully, this beauty can safely be eaten by vegetarians.