Rah Rah Radish

by Ray Novitske, Fairfax Master GardenerRadishes
I enjoy a crisp, sweet, crunchy radish as long as it is not too hot. I always have trouble with them in my vegetable garden, although school children grow them in classrooms because they are so easy to grow and grow fast.

Radishes come in different sizes, shapes, colors and flavors. These root crops can be white, red, pink, purple or green, but are almost always white inside. The radish (Raphanus sativus) is in the Brassicaceae family of plants such as turnips and mustard. We mostly grow it as a root crop, although the top leaves can be eaten, too. Scientists believe their origin to be Southeast Asia where wild forms have been discovered. It is thought to be domesticated only a few centuries ago, since it is only mentioned as an important food ingredient in recent historic texts.

French Breakfast Radishes

French Breakfast Radishes

Radishes are known for their sharp flavor because of certain chemical compounds produced in the plant. Forgive me for mentioning them for our chemical engineer readers: glucosinolate, myrosinase and isothiocyanate. They are a cool weather crop planted in early spring and fall, preferring air temperatures in the range of 50 to 65 F. Because they are fast growing, maturing in three to six weeks, they are perfect for container gardening where they can produce a quick crop before another later plant takes their place.

Plant radishes in early spring as soon as the soil can be worked. Sow seeds in containers or in ground containing fertile, loose soil with good drainage to prevent rot. They germinate and grow quickly and should be thinned out once they develop their first pair of leaves to prevent overcrowding. They can withstand heavy frosts, so don’t worry too much about freezing.

Daikon Radishes

Daikon Radishes

Radishes are sometimes grown as companion plants and suffer from few pests and diseases. One pest, however, is common in our area. Flea beetles will emerge at this time of year to feast on the leaves. If you see very small holes in the leaves, you see the work of these beetles. They can be tolerated, but if becoming too numerous, a quick dusting of safe insecticidal soap, neem oil or diatomaceous earth can cut down populations.

The trouble I usually have with radishes can be traced to growing conditions. Waiting too late in spring to plant them can force their growing season into warm weather, especially in Fairfax County where our winter weather can turn to summer heat in a few days. This causes the plants to ‘bolt’ or grow tops with stems and flowers, but no radishes. This condition can also be caused by planting them too thickly or applying excessive nitrogen fertilizer.

Flea beetle damage

Flea beetle damage

Problems with growing conditions can also cause radishes to become tough and bitter, or very hot and peppery. Leaving the plants in the ground past their optimal harvest time can cause these issues, along with splitting and bolting. It is important to harvest them as soon as the roots begin to poke out of the ground. Later-maturing varieties like Icicle or French Breakfast radishes usually withstand heat better than the early varieties and are recommended for late-spring planting.

One note about the white Daikon radishes popular in Japan and Korea cuisine. These radishes grow a longer tap root and are noted as an effective fall crop to help loosen compacted soil.

Consider one of the many types of radishes for your garden, as an addition to your salads or as a garnish for Korean or Mexican dishes this spring.

Korean Pickled Radish
2 cups water
1 cup rice vinegar
1/3 cup (140 grams) sugar
1 teaspoon (15 grams) salt
1 tablespoon gochugaru (Korean chili powder)
Radishes, peeled and thinly sliced, into about 8 slices each

Combine all the ingredients except for the radishes/daikon in a pot and simmer for 10 minutes, then cool completely.
Transfer to a sous vide bag, add the radish and vacuum seal. If you don’t have access to a vacuum sealer, you can place in any air-tight container to pickle overnight. Serve as a garnish.