radishes ready to be harvested from the garden
Updated: June 10, 2021

Planting radish facts

  • Hardiness: Hardy annual. They can withstand heavy frosts in spring and fall.
  • Planting: Sow seed as soon as the soil can be worked in the spring. Storage roots become spicy hot and woody with rising temperatures. Can also be planted in the fall. Plant a small number of seeds every five days for several plantings to have a steady supply of radishes, rather than one large harvest. Full sun requires direct light at least 6 hours/day; prefers 8 - 10 hours/day. 
  • Days to maturity: 25 - 35.
  • Spacing: Plant seeds 1 - 2 inches apart in-rows and ¼ - ½ inch deep, or equidistantly in wide rows or beds, depending on the variety. Gently cover seeds with a very thin layer of soil. When they germinate, thin the seedlings so that the remaining plants are 2 to 4 inches apart depending on the type.
  • Fertilizer needs: Low. Avoid excess nitrogen to prevent excessive top growth at the expense of roots. Refer to Fertilizing Vegetables for details.
  • Approximate yield: 3 lbs. per 10-foot row.

Growing and care of radishes

  • There are several types of radishes- small spring, Asian daikon, and winter storage cultivars. Storage roots (“the radish”) become spicy hot and woody when over-mature or when grown in hot weather.
  • Plant in fertile, loose soil with good drainage. Radishes germinate and grow very quickly and are sometimes used to mark the rows of slower germinating crops, such as carrots, beets, lettuce, and kohlrabi. Simply sprinkle a pinch of radish seed in the row with these other crops as you plant. The radishes will spring up in a few days, defining each row. The radishes are harvested before their companion crop reaches a mature size.
  • Watering - keep evenly moist but not wet. 

Harvesting radishes

  • Radishes will push out of the ground as they grow and mature.
  • Harvest spring radishes when they are about one inch in diameter, depending on the cultivar, and before they crack, become pithy, or too hot.
  • Cut the taproot and stem from the radish.
  • Radish is in the cabbage family. The foliage and seedpods are edible especially the 'Rat-Tailed' cultivar).

Storage and preservation  

  • Wash, dry, and place in plastic bags. Cool (32 degrees -40 degrees F), moist (95% RH) conditions; 1 to 2 weeks.