Radishes are a cool-season vegetable that can mature very quickly. The small, round varieties will get woody if grown in hot temperatures. Radishes are direct seeded in the garden. They can be started very early in the spring, as soon as the ground is relatively dry and can be worked and again in late fall, in cold frames.
Hardy and quick to mature, successive plantings in early spring and again in early fall will ensure a steady supply of crisp, piquant roots. A good source of vitamin C, they also make a good companion plant in the garden. And every part of the radish is edible!
The peppery roots are familiar as a component of appetizers, salads, and tea sandwiches, but they can also be roasted, steamed, or sauteed. Tendergreen tops add zing to any salad, and immature seed pods have a marvelous sharp taste that makes them a natural in soups and stir-fries.
Planting the Seeds
Radishes can be squeezed in between other plants and are good at loosening and cultivating the soil for slower sprouting vegetables, like carrots. Sow seeds 1/4 to ½ inch deep. You’ll want at least and 2 inches between plants, but seedlings can be thinned and eaten when they are an inch or two tall.
Pests and Problems
Cabbage Root Maggots are more of a problem in northern gardens, where they will tunnel into radishes. Cutworms can also feed on radishes. Flea beetles will make Swiss cheese of radish leaves, but don’t injure the bulb. Monitor to catch these insects before they destroy the whole crop. You can avoid them almost entirely by growing your radishes under row covers.
Radishes decline in quality when the temperature warms. They can get tough and woody or spongy with hollow centers. Once a radish bolts, or goes to seed, the bulb stops forming.
Harvesting Radish
It’s important to harvest radishes before the roots turn woody and bitter. To harvest early roots, simply pull them from the ground when they’re the size of large marbles, and brush off excess soil. Wash well just before use, and store leaves separately from the roots for longer storage in the refrigerator.
For spring and summer varieties, it’s important to harvest them pronto, as leaving them in the ground after maturity will result in rapid deterioration of their taste and texture. After picking, trim the tops, brush off soil, and store in plastic bags or a covered dish in the fridge. If you do choose to wash them off right away, be sure to pat them dry to prevent rot.
The greens of spring and summer types will only keep in the refrigerator for about 2-3 days. But the roots will keep for 5-7 days. Winter varieties are a bit different, as they can be left in the ground until the first frost without any flavor deterioration.
They’re also very cold hardy and will keep in moist storage for several months. In the refrigerator, they can be stored for several weeks. For long-term storage in root cellars, line a box with a thick layer of stray and lay in the radishes, then layer with straw, a bit of soil, then more straw.
Or, after the first frost, you may choose to harvest and then ground trench them outdoors in the same manner. Dig a trench several inches deeper than the roots are wide, add a thick bed of straw, the radishes, more straw, some soil, and a top layer of straw.