Gardener experiments with radishes

In a discussion about squash bugs last spring, a gardening acquaintance said she plants radishes with her zucchini and does not have problem with the dreaded squash bugs. I attempted to try that earlier in the season, but when the first radishes popped up, Pam, my wife, thought they were weeds among the zucchini and pulled them up. No problem.

Radishes grow fast, and I will plant more now that my wife is aware of my scheme. I failed to tell Pam they were to be left to flower and go to seed to keep the bugs away, so we had radishes in our salad and bugs in the squash.

Fortunately, in Mid-Missouri, we can grow a fall crop of zucchini and radishes, so the experiment continues with all parties totally informed of the process. According to the MU Extension website, you can plant radishes all the way to the end of August and probably later with some of the early varieties. For the zucchini experiment, you probably should get an early variety and get it going or buy plants at the garden center.

While I was looking around on the site, I noticed David Trinklein, University of Missouri Division of Plant Sciences, had an interesting article for "impatient" gardeners. Here is some interesting information from that article to consider about radishes, a quick growing vegetable, the "Perfect Crop for Impatient Gardeners."

Some varieties are ready to harvest in as little as three weeks after sowing seeds. Most of the later varieties take only four or five weeks from planting to harvest. Whatever a gardener's level of patience, August is the ideal time to sow radishes in Missouri.

Radishes are a member of the Brassicaceae family, which includes cabbage, broccoli and cauliflower. Most people think of radishes being eaten raw out-of-hand or in a salad. However, in other parts of the world, different types of radishes are used in many ways.

For example, varieties of radishes have been developed from which only the leaves are consumed. Other varieties have been developed for their long seed pods which are eaten. In the Orient, radishes are often eaten after being pickled in brine. Additionally, certain types of radishes are grown for livestock feed while others have oil-rich seeds.

The rapid-maturing varieties usually have white flesh surrounded by red skin. One of the most popular early varieties is Cherry Belle. It is round, red and ready to eat in about 24 days following planting. Champion and Sparkler are also excellent variety for sowing in late summer or early fall. Both are bright red and ready to eat in about three weeks after seeding.

While other good red, round varieties exist, there also are several very useful white types. Snow Belle is very similar to Cherry Bell other than its skin is white instead of red. White Icicle is an excellent older variety with white skin and an elongated root not unlike that of a small carrot. A rapid grower, White Icicle requires about a week to 10 days longer to mature than other early types.

For those who like the unusual, there are newer varieties of radishes that come in different colors. Black Spanish has white flesh surrounded by dark, blue-black skin. Easter Egg, another newer variety, produces small oval roots in several skin colors including pink, red, purple, violet and white. Regardless of the skin color, the flesh of Easter Egg is white.

Radishes are a frost-hardy vegetable that needs cool temperatures to grow best and have the best flavor. Radishes grown in warm or hot weather become pungent or "hot" with age. The latter is due to compounds called allyl isothiocyanates, which also are present in horseradish and mustard. This makes early fall an ideal time to grow radishes, as they will mature in the cool fall weather.

Seeds of radish may be planted up to ½ inch deep and plants thinned to about 1 inch between plants within rows. Planting wide rows 8-12 inches across is a space-saving way to grow them. To have too many radishes maturing at one time, sow small quantities of seeds at weekly intervals. Roots that are not harvested promptly after maturing tend to become pithy and loose quality.

The main insect pests of radishes include aphids and flea beetles. If they become too problematic, insecticidal soaps or other pesticides may be applied to control them.

A frequent complaint from gardeners is their radishes have huge, lush leaves but roots that are too small to eat. Most often, this condition is the result of over fertilization with nitrogen. Radishes will produce a better crop in soils that are not overly fertile. Also, avoid using fertilizers high in nitrogen on soils destined to be planted to radish. A fertilizer high in phosphorus, such as superphosphate or bone meal, will bolster root development. Additionally, loose, porous soils also allow for rapid root growth and the development of radishes with good size and shape.

Some radish trivia:

• Americans consume about four million pounds of radishes each year.

• Ancient Egyptians used radish seed oil before olive oil was available.

• In centuries past, radish was used to treat kidney stones and as a blood purifier.

• Noche de Rabanos (Night of the Radishes) is a festival that takes place in Oaxaca, Mexico, just 24 hours prior to Christmas Eve. Radish carving is a highlight of the festival.

• Along with onions and garlic, radishes were used as wages for the Ancient Egyptians who built the pyramids.

• The world's largest radish weighed 68 pounds, 9 ounces and had a circumference of more than 46 inches. It was grown in Japan in 2003.

Happy gardening!

Peter Sutter is a lifelong gardening enthusiast and a participant in the MU Extension's Callaway County Master Gardener Program. Gardening questions can be sent to [email protected].