What might be surprising for many is that radishes are from the same family as cabbages. Unlike the cabbage, however, it's the radish's root that is prized, and not the leaves. Radishes come in a wide number of varieties--over 100, in fact--though perhaps the most common is the red radish. If you are keen to grow them in your garden, becoming familiar with the life cycles of the radish can be useful information.
The first stage in the life cycle of the radish is germination. Germination for radishes is rather quick. In fact, it can take place within a week or even several days. Unlike other plants, it's not necessary to start the process of germination indoors in the winter months. Soon after the last hard frost, radishes can be sown directly in the ground.
Seedlings are the next stage in the radish's life cycle. In order to encourage this growth, you'll need to thin the rows a couple of weeks after sowing to enable the radishes to grow to their full potential. It is also necessary to make sure weeds don't crowd out the young seedlings as they grow, robbing them of the necessary nutrients.
The first leaves resemble clover, then, after about two or three weeks, others begin to grow longer and broader. As the leaves grow, keep track of the plants to make sure that they are not crowded. Beneath the ground, the roots will extend downward as the bulb begins to grow.
As the plant matures and the leaves become fuller, the bulbs continue to grow. Within a month, the bulbs develop the color that typifies the variety, from scarlet to purple to white.
The radish is ready to harvest when its bulb reaches an inch or more, generally 30 to 40 days after being sown, though sometimes longer (depending on the variety and growing conditions). With the tops removed, the radishes can be refrigerated for up to a week. With the tops intact, they can last up to 3 days.
Radishes can be planted throughout the growing season, thanks to their quick growing cycle.