Radishes are grown and consumed throughout the world, being mostly eaten raw as a crunchy salad vegetable with bite. There are numerous varieties, varying in size, flavor, color, and length of time they take to mature. Radishes owe their sharp flavor to the various chemical compounds produced by the plants, including glucosinolate, myrosinase, and isothiocyanate. They are sometimes grown as companion plants and suffer from few pests and diseases. They germinate quickly and grow rapidly, common smaller varieties being ready for consumption within a month, while larger daikon varieties take several months. Being easy to grow and quick to harvest, radishes are often planted by novice gardeners. Another use of radish is as a cover or catch crop in winter, or as a forage crop. Some radishes are grown for their seeds; others, like daikon, may be grown for oil production. Others are used for sprouting. 1. Decide what variety of radishes you want to plant. Like many vegetables, there are innumerable varieties of radishes at your disposal, both hybrid and open-pollinated. If you are a novice gardener, consider growing Cherry Belle radishes; they mature in just 22 days and have a pleasant, mild flavor.

-Typically the summer radish is similar to the spring radish but tends to grow more slowly, taking around 6-8 weeks to mature.

-Make sure your radishes are getting plenty of sunlight. Otherwise, they will grow big on top and very small in the root section. However, too much sunlight can cause radishes to go to seed.
-The soil needs to be free of rocks, well-drained and have a pH content of around 7.4. This high pH content helps prevent club root, a brassica-infecting fungus that causes plant roots to swell, misshape, crack, rot and sometimes lead to plant death. To raise the pH, add dolomite lime or agricultural lime in autumn. Use plenty of organic matter (like compost) in the soil.

-The soil needs to be free of rocks, well-drained and have a pH content of around 7.4. This high pH content helps prevent club root, a brassica-infecting fungus that causes plant roots to swell, misshape, crack, rot and sometimes lead to plant death. To raise the pH, add dolomite lime or agricultural lime in autumn. Use plenty of organic matter (like compost) in the soil.
-For best results, conduct a soil test or send soil samples to a lab to check for proper nutrients. Make any adjustments to the soil at least one week before planting.

3. Schedule your radish plantings. Radishes are a cool weather crop best planted in spring and autumn. Growing radishes during the hot summer months may cause them to bolt. You can plant your first crop a full 2 weeks before the last frost in spring, as radishes endure frost well.
-Stop growing when hot weather shows up. This basically means that if you're having consecutive days of 60 °F (16 °C) or above you should hold off on your radish planting until it gets cooler.
-A typical spring radish germinates in about 5 days and is ready for harvest in 3 to 4 weeks.
-Because radishes grow so quickly, you can "inter-crop" them between slow-growing vegetables to make row markers. You can also "succession plant" them by sowing a new row each week, to spread your harvest over a longer period.

4. Sow the radish seeds. You will want them to be about 1/2 inch (12.5 mm) deep and 1 inch (25 mm) apart. As they germinate, thin the successful seedlings to about 2 inches (5 cm) apart, allowing more space for bigger varieties. Rows should be planted about 1 foot (30 cm) apart.
-You will want to thin the radishes when they have grown about 1 inch. Aim to just cut off their heads with a small pair of scissors, all the way down to the soil.
-If you're planting a large radish you will want to plant the seeds about 1 inch to 1 1/2 inch deep.
-Radishes work well as companion plants, because they keep a lot of the bugs off the regular plants and they grow more quickly. Plant them alongside carrots, parsnips, and cabbages.

5. Water the radishes as they grow. Keep the radish beds moist, but not soaked. Watering radishes frequently and evenly will result in quick growth; if radishes grow too slowly, they will develop a hot, woody taste. Add compost to the radish bed as desired to help retain moisture.
-If you don't water them evenly (for example, not watering for a few days and then drowning them) the radishes can crack.

6. Harvest the radishes. Radishes are typically ready to harvest when their roots are about 1 inch (2.5 cm) in diameter. Check your seed packet for your variety's expected size at harvest and time to maturity. To harvest, lift the entire plant out of the ground with your hand.
-You can also push back the dirt and see if a bulb has grown. If so, pull a few radishes and taste them. That will let you know if they're ready to be harvested.
-Unlike many root vegetables, radishes cannot be left in the ground, as doing so will cause them to become tough and pithy.