How To Grow Radishes
Plant Type: Annual
Scientific Name: Raphanus sativus
Light: Full sun
Soil Type: Well drained, high organic material
Soil Temperature: 40° +
ph Range: 5.5 – 7.0
Watering: Consistent moisture
Plant (Payson): March 15 – May 10 / August 15 – September 15
Planting Method: Seed
Germination: 3 – 4 days @ 55°
Transplant: Not recommended
Maturity: 25 – 35 days
Common Pests: Cabbage root maggot, flea beetles
Common Diseases: Clubroot
Crisp and peppery, radishes are easy to grow. Sow as soon as soil can be worked in early spring. Repeat at 7-10 day intervals until warm weather approaches. Sow again a month before frost for a quick fall harvest.
You can pull radishes for the table 3 weeks after you sow the seeds (the slowest types take 2 months). Radishes grow best when the temperature ranges between 50 and 70 degrees.
Loosen soil 6-10 inches deep and blend in compost or well-rotted manure before planting-or side dress about 10 days after planting.
Direct sowing is recommended.
Sow seeds ½” in. deep 1 inch apart in rows spaced 12” apart. Thin to 3” apart when tops are visible. Seeds typically sprout three to seven days after planting in 60-degree soil.
Keeping the radish bed well mulched will help keep the soil cool and moist.
Keep the soil continually moist. Planting alongside plants which will provide some shade in the summer will prolong their harvest. Radishes love sunshine but only in cool weather.
Feed ½ cup of a organic nitrogen based fertilizer beside the row ten days after emergence. Water it in after application.
Radishes do not compete well with weeds, especially at time of germination and early establishment. Avoid deep cultivation around the plants or you may damage the radish and lessen the yield.
Downy mildew, root rot.
Flea beetles make holes in radish leaves. Cabbage root maggots and cutworms rasp holes or channels into radish skins. All of these pests can be easily prevented by using floating row covers.
Harvest radishes as soon as the roots become plump, roughly 3 to 8 weeks after planting depending on the variety. When harvesting in warm weather, cool radishes right away by dropping them into a pail of cold water. Refrigerate after removing leaves with a sharp knife or kitchen shears.
Hot weather and lack of continued moisture encourage development of spicy flavor compounds similar to those found in horseradish.