Raphanus raphanistrum subsp. sativus

Radishes have been in cultivation for thousands of years and are grown all over the world. The fleshy taproots range from 1 inch to 3 feet long depending on the cultivar and come in colors including white, pink, red, purple and black.  They are fast growing vegetables, ready to harvest in 3-6 weeks, making them great for use in a children's garden.  The edible white or pink flowers have a spicy flavor and are often used in salads.  The leafy tops can also be eaten and are best cooked to improve the texture.  While most commonly grown for food, they are also grown for livestock forage and as a cover crop for breaking up compacted soil.

Radishes grow best in full sun to part shade and a well-drained loamy or sandy soil.  While they can grow in partial shade, at least 4 to 5 hours a day, it will take longer for the root to grow to a harvestable size.  Lighter, looser soils will yield a smoother, rounder, and more tender root.  Light soils need to be watered more frequently and consistent moisture is needed to produce a good flavor.  Roots will turn woody with age, hot weather, and if the plant bolts, although if this happens the flowers can be harvested and used instead.

Radishes are a cool-season crop and grow best in spring and fall.  In NC, plant seeds sometime in mid-February to early April for a spring crop and from August to mid-September for a fall crop.  Plant the seeds of smaller cultivars 1/4 to 1/2 in deep and larger cultivars up to 1 in deep.  Thin small varieties to 1-3 in apart and large varieties 4-6 in.  Longer varieties need deep soil that raised beds readily provide, at least 2-3 feet deep; smaller varieties can easily be grown in containers at least 2 quarts in size and 4-6 in deep.  Plant new seeds every 2 weeks to extend the harvest.

Radishes are ready to harvest in as little as 3-6 weeks, whenever they reach a useable size.  They are ready when you can see the tops start to peak through the soil.  Small varieties can be pulled by hand; for large varieties, use a spade or fork to help pull the root from the soil.  Small roots last 1-2 weeks in the fridge while large ones like Daikon can last up to 2 months.

Insects, Diseases, and Other Plant Problems: While diseases are less commonly a problem, look out for insects that damage the roots such as flea beetles and root maggots.  Swede midge may attack the leaves, causing crinkling and distortion.  It may cause contact dermatitis in some people.