F1 radishes are a hybrid variety grown by using two selected radish types to produce a superior radish. Gardeners refer to the resulting crop as an F1 variety because the radish is in its first generation of production. When you grow F1 radishes, you are growing a new breed of radish that offers the best of both parent plants. Growing F1 radishes gives you the opportunity for better taste, shorter growing seasons, and more uniform root bulbs. F1 radishes are more resistant to disease and insect problems, as well.
Prepare the garden bed as soon as the soil is workable. Add a quality organic fertilizer while tilling or spading the garden site. Break up the large clumps of soil and remove any rocks. Rake the soil to ensure a smooth planting bed.
Form a trench a half-inch deep. According to Douglas Sanders, horticultural specialist from North Carolina State University, space the seeds approximately 3/4 inch apart or 18 plants per foot with 6 inches between rows. Cover the seeds with the soil and water.
Thin the radishes so there is at least 1/2 to 1 inch between plants, if needed. Roots will not develop on F1 radishes planted too closely together.
Water on an even schedule during root development. Information from the University of Illinois states radishes split and become woody from uneven moisture while growing.
Harvest the F1 radishes after 25 to 30 days, depending upon the variety. Longer growing periods results in hot or pithy radishes. Plant another crop as soon as the first group is harvested to produce even more radishes.