Radish IntroductionRadish is a member of the Cruciferae (mustard family). Raphanus sativus is a cool season annual (depending on when it is planted). Radishes have been cultivated for thousands of years in both China and the Mediterranean area. Radishes were a common food in Egypt before the building of the pyramids and is one of our most ancient cultivated plants. Generally commercial radishes are approximately 2 cm in diameter and are either red or white. They reach market size in 21 to 28 days (or longer in cool weather). There is also a radish group called daikon (Longipinnatus group) which is the Chinese oriental radish. These may grow up to 75 cm long with a diameter of up to 25 cm. These may weigh several kilograms. Radish vary in color from white to black.
Radish is a quick growing cool season root vegetable. The seed will germinate in 3 to 4 days with soil temperatures of 18º to 30ºC with good moisture. The minimum temperature for germination is 5ºC, the optimum temperature for germination is 30ºC. The maximum temperature for germination is 35ºC. Germination rates decline sharply when the soil temperature falls below 13ºC. The best quality and root shape are obtained when the crop grows and matures at moderate temperatures (10 to 18ºC) in intermediate to short day lengths. Radish remain in prime condition for only a few days. Roots of globe varieties tend to elongate and develop poor shape in hot weather when the tops also grow taller and larger than in cool weather. Long days induce flowering or seed stalks (bolting) and with warm weather the seed stalk may develop so rapidly that no edible root is formed. Radishes become more pungent in hot weather. Roots remain in marketable condition only a short time before becoming pithy. Growth must be continuous and rapid for good quality.
This crop requires a well drained sandy loam or loam with a good supply of organic matter as well as an even moisture supply for good quality (mild, tender and attractive). Rocky or gravelly soils are generally not acceptable especially if bed harvest is to be used. Peat soils are also suitable for production of radish.
Regular radish reach market size in 21 to 28 days so crop can be on the market from June to the end of October. Chinese radish take 50 to 90 days to mature. These become available to market in August and with storage can be marketed into November and December. Yields per hectare depend on the variety and the number of crops per year. Regular radish yield 10,000 to 15,000 kg per hectare. Chinese Radish may yield 30,000 to 44,000 kg per hectare.
Currently radish is a minor crop and markets are quite limited, but there is room for a few growers to supply regular radish, wholesale (bunching and cello pack), and especialty markets with Chinese radish.
Nutrient Content: Good source of Vitamin C, potassium and magnesium, plus trace amounts of other nutrients. Four radishes supplies 5 kilocalories.