HOW TO PLANT RADISHES
For a spring planting, sow seeds 4–6 weeks before the average date of the last frost.
It is best to plant radish seeds directly in the garden so as not to disturb their roots. Directly sow seeds outdoors ½ to 1 inch deep and 1 inch apart in rows 12 inches apart.
Plant another round of seeds every 10 days or so while the weather is still coolad for a continuous harvest of radishes in the late spring and early summer.
Plan on a fall planting. You can plant radishes later than any other root crop in late summer or early fall and still get a harvest. Sow seeds 4–6 weeks before the first fall frost.
Thin radishes to about 2 inches apart when the plants are a week old. Crowded plants do not grow well.
Consistent, even moisture is key. Keep soil evenly moist but not waterlogged. A drip irrigation system is a great way to achieve this.
Putting a thin layer of mulch around the radishes can help retain moisture in dry conditions.
HOW AND WHEN TO HARVEST RADISH
Radishes will be ready to harvest quite rapidly, as soon as three weeks after planting some varieties.
For most varieties, harvest when roots are approximately 1 inch in diameter at the soil surface. Pull one out and test it before harvesting the rest!
Do not leave radishes in the ground long after their mature stage; their condition will deteriorate quickly.