How big a pot would depend on how many radishes you’d like to grow in one container. The pot should be at least 6 inches deep (4 inches may do for the smaller types of radishes). Make sure that the container has drainage holes. Check the recommended spacing for the radish variety that you’d like to grow, and then you can plan the width of the pot. Window boxes often do well, for example.
How big a pot would depend on how many radishes you’d like to grow in one container. The pot should be at least 6 inches deep (4 inches may do for the smaller types of radishes). Make sure that the container has drainage holes. Check the recommended spacing for the radish variety that you’d like to grow, and then you can plan the width of the pot. Window boxes often do well, for example.