The Best Way to Grow Radishes From Seeds

Removing the tops right after harvest keeps radishes from wilting.

Radishes germinate and mature quickly. They take up little garden space, can be sown between plants that develop more slowly, and grow well in containers. A cool-weather crop, radishes are usually grown in the spring, but midsummer plantings produce a late crop that matures during cool fall weather. The key to growing both early and late radishes with crisp flesh and good flavor is getting them to maturity quickly, a process that requires fertile, well-drained soil and regular watering.

Things You'll Need

• Potato fork or spade
• Sand
• Compost, composted manure or peat moss
• All-purpose fertilizer
• Row covers
• Drip irrigation system
• Wood ashes

Instructions

1. Locate radishes in a spot in the garden that receives the appropriate amount of sun. They can handle partial shade, but prefer full sun. You can plant radishes either in a series of single rows or a wide row. You may also scatter radish plants among other vegetables. Avoid planting radishes where members of the cabbage family were grown in previous years.

2. Purchase fresh, high-quality seeds to grow the best radishes. Planting a mixture of several radish varieties, including both early- and late-maturing cultivars, will help you learn which varieties grow best in the conditions your soil and climate offer.

3. Loosen the soil with a potato fork or spade, cultivating to a depth of 6 inches. The best soil for radishes is sandy loam with plenty of organic matter. If your soil doesn't measure up, dig in 2 to 4 inches of compost or composted manure.

4. Sow the seeds for the first planting ½ to 1 inch deep and 1 inch apart as soon as the ground can be worked in the spring. Sow seeds in late August for a fall crop. Space the rows 6 to 18 inches apart, depending on the variety.

5. Keep the seeds uniformly moist until they germinate in five to 10 days. When the sprouts are 1 to 2 inches tall, thin to 3 inches apart.

6. Side-dress plants with a nitrogen-based fertilizer at the rate of ¼ cup per 10-foot row for quick growth.

7. Water deeply and regularly to produce mild-tasting radishes. Drip irrigation is ideal. For radishes grown in rows, adding mulch between the rows can help retain moisture and reduce competition from weeds.

8. Repel root maggots by covering new plants with row covers or sprinkling wood ashes on the ground around the radish plants.

9. Harvest radishes as soon as they reach full size, which occurs between 25 and 45 days from sowing the seed. If you leave them in the ground too long, radishes become tough and develop a strong, hot flavor.

Tips & Warnings

• Let a few radishes go to seed. The little seed pods can be added to salads when raw or cooked as a green vegetable.

• Root maggots are a spring pest, so fall crops will not be bothered by them.

• Winter radishes can be stored in damp sand, sawdust or peat moss at 40 degrees Fahrenheit for up to two months.

• Don't sow radish seeds if the soil is muddy; it may cause them to crack.

References

• Utah State University Extension; Radishes in the Garden; Dan Drost, et al.; November 2004
• University of Nebraska--Lincoln Cooperative Extension; Growing Radishes and Table Beets; Susan D. Schoneweis; 1990
• Oregon State University Extension; Bolster Gardening Confidence by Growing Radishes; Carol Savonen
• "The Garden Primer"; Barbara Damrosch; 1988

Resources

• University of Maryland Extension; Radish; John Traunfeld, et al.; March 2010