When to Plant: Direct sow seeds outdoors in early spring as soon as the soil can be worked, or in late summer for a fall crop. Avoid planting in hot weather, as this can cause the plants to bolt (flower), resulting in bitter, woody roots.
Location: Choose a spot that receives full sun, though partial shade is beneficial in warmer climates to prevent excessive heat.
Soil: Radishes thrive in loose, rich, well-draining soil with consistent moisture. Amend the soil with compost before planting, but avoid high-nitrogen fertilizers or fresh manure, which can encourage leafy growth at the expense of root development.
Sowing: Sow seeds about 1/2 inch deep and 1 inch apart. Once seedlings are established, thin them to 2-3 inches apart to give the roots enough space to swell; overcrowding can prevent root development.
Watering: Keep the soil consistently moist. Inconsistent watering can lead to pithy or split roots.
Succession Planting: For a continuous supply of radishes, make small, successive plantings every 1-2 weeks during the cool growing seasons.
Harvesting
Harvest the radishes promptly when the roots reach about 1 inch in diameter, which is typically around 3-4 weeks after planting. If left in the ground for too long, they will become too large, woody, and overly pungent. The greens can also be eaten.