Radish (Raphanus sativus)

Grown and consumed throughout the world, radish (Raphanus sativus) is an edible root vegetable member of the Cruciferae (Brassicaceae) or mustard family.  China is believed to be the country of origin and middle Asia appears to be a secondary location where many different forms developed after the plant was introduced from China in prehistoric times.  Ancient writings show that it was popular in Egypt during the time of the pharohs. 

   Raphanus is the Latin form of the Greek word for radish and is said to originate from a phrase meaning ‘easily reared’.  Referring to the bright red colour of the vegetable, the word ‘radish’ is derived from the Saxon, ruderudo, or reod (ruddy), or from the Sanskrit rudhira, meaning blood.  These plants are a staple food in Japan and China, where they are often pickled in brine, preserving them for long periods of time.

Radishes have often been dismissed as decoration and garnish but are actually members of the cruciferous vegetable family.  Rich in ascorbic acid (vitamin C), folic acid, potassium and fiber, radishes are also a good source of vitamin B, riboflavin, magnesium, copper, sulphur, iron, iodine, and calcium. They are used in alternative treatments for a variety of illnesses including coughs, cancer, whooping cough, liver problems, constipation, gallbladder problems and stones, arthritis, and kidney stones.  Winter radishes, such as daikons, are similar in nutrients.  Radishes are low in calories, 1 cup (250 mL) equals 20 calories, and provide an abundance of flavour and crunch. 

   Shredded radish can be added to vegetable juice to spice up the flavour and in this form can help clear sinuses and soothe sore throats.  Vitamin C in radishes is an anti-oxidant and anti-inflammatory and has been shown to have a positive effect on asthma symptoms.  Potassium is believed to lower the risk of kidney stones and strokes, and radishes along with a diet high in other fruits and vegetables is thought to significantly lower the risk of multiple sclerosis.

   Radishes can be categorzied into four main types: spring, summer, fall, and winter.  They come in a variety of colours, shapes, and sizes, most commonly the red-skinned variety but other varieties may have a pink, white or gray-black skin, and there is a yellow-skinned variety.  Some varieties are black or multi-coloured, with round or elongated roots that can grow longer than a parsnip. 

   Spring and summer radishes require very little room to grow and mature quickly, with many varieties germinating in 3 – 7 days, and reaching maturity in three to four weeks as long as adequate moisture is maintained.  Slow development makes radishes woody in texture and hot in taste. They do well in containers, flower beds, and small gardens.  Summer radishes are a cool season crop and grown in the spring here in the north.  They are generally grown for the root, usually eaten raw, although the entire plant can be eaten and radish greens can be used as a leaf vegetable, either cooked or used raw in salads.  Spring and summer radishes are a good crop of vegetables to grow in children’s gardens.

   Winter varieties take their name from their ability to be stored during the non-growing winter months.  They can be grown throughout the growing season, are generally larger than the summer varieties, and cultivation often takes six to eight weeks. 

   Radishes do best in six hours of full sun and moist, fertile, acidic to neutral soil. Make successive plantings, spaced a week or two apart to extend the harvesting period.  Plant radish seed 1/4 – 1/2 inch (6 – 12.5 mm) deep and thin spring varieties 1/2 – 1 inch (12.5 – 2.5 cm) apart.  Winter radishes need to be thinned 2 – 4 inches (5 – 10 cm) apart for proper development of their larger roots.  Radishes may be broadcast lightly and thinned to 2 – 3 inches (5 – 7.5 cm) apart in all directions if seeding in beds.  Although spring varieties grow best in the cool days of early spring, some later maturing varities can be planted for summer use. 

   Sowings of spring radishes can begin in late summer in the cooler days of autumn and winter types are sown in mid-summer to late summer.  Winter radishes are slower to develop, grow larger, remain crisp longer, are more pungent, hold in the ground, and store longer than spring varieties.  To maximize the use of garden space, plant spring radishes between slow-growing vegetables or in areas that will be used later for warm season crops.  Spring radishes can be planted in late winter in containers or window boxes and grown in the house, on the patio, or in a protected cold frame.  Radish seeds can be sprouted and used in salads or sandwiches. 

   Following flowering, the seeds of radishes grow in pods that happens when left on the plant past their normal harvesting period.  The seeds are edible and can be used as a spicy addition to salads.  Some varieties are grown specifically for their seeds or seed pods.  

   In the kitchen, radish can be braised, steamed, sautéed, and used in salads, dips, soups, sandwiches, stir fries, or pickled.  When serving, you can soak radish in ice water for an hour or two for extra crispness; or you can braise thin-sliced daikon in a bit of sesame oil and serve hot for an Oriental treat.  Summer and winter radishes are most often eaten raw.  Use a stiff vegetable brush and scrub radishes under cold running water. Do not peel summer or black radishes. Pare away the top and root end then slice, dice, shred, or serve whole.  Daikon radish are always peeled.

   In the garden, plant with cucumbers, squash, and melons to repel the striped cucumber beetle, and with tomates to rout spider mites.  Plant two or three radish seeds in each squash hill.  Let the radishes grow and go to seed.  They grow well with bush beans, pole beans, and kohlrabi.  Growing leaf lettuce near radish will make the radish more tender.  Radish should never be grown near hyssop. 

 

Cooking Hints

  • For extra crunch and bite, add sliced radishes to stir-fry’s.
  • Sprinkle chopped or sliced radishes into tuna for more zip and texture.
  • Stir chopped or sliced radishes into tuna, egg, potato or chicken salad.
  • Thinly sliced radishes make a tasty, fresh garnish sprinkled over New England clam chowder or other milk-based soups.
  • For an unusual vegetable side dish, sauté quartered radishes in butter until crisp-tender, about 2 minutes; sprinkle with cracked black pepper.
  • Stir chopped radishes into plain yoghurt or sour cream for a topping for baked potatoes or chili.
  • Bagels spread with cream cheese and sliced radishes make a quick appetizer or snack.
  • Roast radish halves brushed with oil at 450° F (230° C) for 15 minutes. Great with roast beef or chicken.
  • A combination of mayonnaise and chopped radishes makes a tangy instant spread for ham or roast beef sandwiches.
  • Thinly slivered radishes stirred into rice pilaf add an unexpected zip and crunch.
  • Toss radish greens (full of vitamins A, C, and B) into mixed vegetable soups or stir–fry’s.  They cook quickly.  If they are young and tender toss into a green salad.

Harvesting

Harvest summer radishes when they are relatively young and the roots are less than 1 inch (2.5 cm) in diameter.  Save the young thinnings of both summer and winter radishes. They are delicious with tops and bottoms intact.

   Harvest winter radishes when they are large and mature as they should be harvested at a much larger size.  Once mature, they will maintain high quality for a fairly long time in the garden, especially in cool fall weather.

How to Buy

Radishes come in several varieties, although the most common in North America is the oval, red-skinned verison.  Look for unblemished and bright coloured skin, a firm compact texture, and short, bright green leaves.  Daikon (Chinese) radishes are sometimes available in grocery stores but primarily sold in Oriental speciality markets. 

How To Store

Summer radish may be bold red, pink, purple, white, or red and white.  Both summer and winter radishes store well in the refrigerator once the tops have been removed. Store greens separately for 2 – 3 days. Refrigerate radishes wrapped in plastic bags for 5 – 7 days.  Winter radish varieties can be stored for up to two weeks in the refrigerator.  Do not freeze radish.

   Winter radishes may be white, black, or green. Black radishes have a pungent flavor and should be used sparingly. Remove greens and roots before storing black radishes. Winter radishes can be pulled before the ground freezes and stored in moist cold storage for up to several months. 

Problems

1) Root maggots.

Root maggotsmay tunnel into radishes. Nylon mosquito netting, fastened to wire hoops placed over the crop, will keep the fly eggs from landing near the plants and hatching into the root maggot larvae.

2) Radishes crack and split.

Pull the radishes when they are younger and smaller.  Too much moisture after a period of dryness may also cause mature roots to burst and split.  Avoid uneven moisture availablity.

3) Grow all tops.

Several reasons can contribute: seed planted too thickly, plants not thinned, weather too hot, or too much shade.

4) Radishes too hot.

The radishes either grew too slowly or they are too old.

Recipes

Pickled Daikon and Carrots

1 cup (250 mL) daikon or other white radish (red globe radishes may be substituted for daikons) 
1 carrot shredded
1 tbsp. (15 mL) canning salt
1 cup (250 mL) water
1/4 cup (50 mL) distilled white vinegar
1 tbsp. (15 mL) sugar
1 tsp. (5 mL) red pepper flakes (optional)

Wash, peel, and shred radishes if using daikon.  Do not peel red globe radishes before shredding.  Put vegetables in a bowl, sprinkle on the salt, and mix well.  Let stand for 30 minutes.  Drain off water and squeeze vegetables as dry as possible.

In a small bowl combine vinegar, sugar, and pepper flakes if using.

Place vegetables in a clean glass jar, pour over liquid, and refrigerate overnight or for 6 – 8 hours before serving.  Stores in the refrigerator for up to 4 weeks.