How to Grow Radishes Fast

Overturn and till the soil to a depth of 8 to 10 inches in a sunny location. Radishes prefer six to eight hours of direct sunlight a day for optimal growth.

Spread a 2- to 3-inch layer of organic matter, such as well-rotted manure or compost over the area. Work this into the top 6 inches of soil. Organic matter improves aeration and promotes good drainage while releasing nutrients into the soil.

Apply 10-10-10 fertilizer following the recommended application rate on the container. Work this into the soil well, as fertilizer damages young roots and seeds.

Choose an early-maturing radish for the fastest growth. Radishes typically mature in 25 to 35 days under optimal growing conditions. However, some varieties, such as cherry belle or scarlet globe mature in as few as 22 to 23 days.

Plant radish seeds in the early spring as soon as the soil is workable. These hardy plants survive the frost and germinate in cool soil.

Sow the seeds to a depth of 1/4 inch, spaced 1- to 2-inches apart, depending on the type of seed. Cover with soil and firm the soil down with your hands to secure the seeds and remove air pockets.

Water the seeds to a depth of 1-inch to moisten the soil. Keep soil moist until seedlings emerge in 5 to 7 days.

Water deeply to moisten the soil to seed root levels at least once or twice a week, or whenever the soil feels dry 1 inch below the surface of the soil.

Harvest radishes when young and tender for the best flavor. As they mature, radishes become woody and the flavor intensifies.