One of the fastest and easiest to grow vegetables, radishes can thrive in almost any climate. Some varieties grow so fast that they can be harvested as little as three weeks after the seeds are planted. Actually, the trick with radishes is not leaving them in the ground too long, or you can end up with woody, bitter tasting radishes.
The great thing about radishes is that they can be grown year round; however, many varieties do best in cool weather. To maintain a continuous crop, you want to sow your radishes every two or three weeks. Another great thing about radishes is that you can plant them in the shadier spots of your garden where other vegetables will not grow. You want to plant your radish seed about 1/4-inch deep and at least 2 inches from one another. Within one to two weeks, seedling should begin to appear. It is important to keep the soil moist during this growing period. You might consider using a liquid fertilizer once a week.
The main pests that affect radishes are white butterflies and cabbage moths. Use a soap shield or Bt to prevent this. Radishes make good companions for vine crops such as pumpkins, melons, squash, cucumbers, beans, carrots, lettuce, and peas. Small radishes are used in fresh salads, as garnishes, and many other ways in cooking.