Radishes, Raphanus sativus L. are a very fast growing cool season crop belonging to the Brassicaceae family. Originating from Asia, their flavors can range from mild to hot. The most familiar radish to Americans may be a round red radish with white flesh and a mild flavor. I don’t like them. When I was growing up, my mother would ruin a perfectly fine potato salad by smothering the top with layers of sliced radishes. I learned how to pick them off and out of things fast. I will grow them, but I really don’t like harvesting them either. Their leaves are covered with fine hairs that feel a lot like thorns poking my flesh. They are there for a reason, and just because I don’t like them doesn’t mean I won’t grow these in my garden. I just won’t eat them. They are a great veggie to grow and share.
There are mainly two types of radishes. Like I mentioned above, the round fast growing radish that is best grown in the spring, and the Daikon radish which should be grown in the fall and is best for winter storage. There are many colors and shapes but all germinate best when soil temperatures are between 45-90 degrees Fahrenheit, with the optimum temperature being 60-65. The soil temperature in my garden right now is 55, so I will be sowing radishes without cover (cold frame) this weekend. Ideally, you want to direct sow about 1/4 to 1/2 inch below the surface in rows spaced about 8” to 18” apart. Sow the seeds in a line. After they have germinated, you will notice that they are too close together, so you need to “thin” them. You will know how much just by picturing the size of the radish when you will be harvesting it. That is how much space it will need to grow, with a little extra in between. If you continue to plant every 2-3 weeks, you will have a continuous harvest for most of the year. Radishes don’t grow very well during hot summers, but if you interplant them between other plants that may shade them to keep them cool, you might surprise yourself with how long you can grow them. For winter radishes, start them at the beginning of September and you will be harvesting through late fall. Daikon radishes are good to grow through the winter in a cold frame and also grow well in raised beds. Traditionally, radishes are the first crop harvested and the last crop sown.
Harvest when they are about the size of a large marble except for Daikon radishes which are so large you need to loosen the soil with a garden fork. If you wait too long, they get too large and mealy. You may wonder how I know this without eating them. Well, I do have radish testers living in my house. So I get my information from them. And if you slice them, they should be nice and crisp. Remove the leaves and wash. Some people like to eat those hairy greens. Do as you choose. Store washed radishes without drying too much in a plastic bag or container in the refrigerator to keep the humidity high and temperatures cool.
Radishes are susceptible to flea beetles and cabbage root maggots. You can avoid this by rotating crops, not planting anything from this plant family in the same place for three years. Using a floating row cover can also help by deterring cabbage moths from laying their eggs on the plants.
Interesting is that the U.S. standards for radish grades hasn’t changed since 1968. It reads “Tenderness, cleanness, smoothness, shape, size, and freedom from pithiness and other defects; tops of bunched radishes fresh and free from damage.” So, if you are growing radishes for someone, these are the standards you should be following.
Want something weird. Grow the radish from Baker Creek Heirloom Seeds called “Rats Tail”. It is an edible-podded radish that produces large seed pods that are good for stir fry and pickling. Maybe I would like this radish? If you grow it, let me know how you like it. For now, I’ll stick with fewer plants from this family in my garden, and learn from all of you brassica lovers.