Sowing red radish: cultivation, care & harvesting

Sowing and planting red radishes: What you need to know

The red radish or also known as german radish, garden radish or common radish (Raphanus sativus var. sativus) is part of the cruciferous family (Brassicaceae) . They are closely related to radishes (Raphanus) and are very similar in taste. Garden radishes are probably native to Asia.

Location & soil

Red radishes are an uncomplicated crop that thrives in almost all garden soils. However, the tubers develop best in loose, humus-rich soil . Beds with heavy soil should be loosened before sowing so that the tubers can grow unhindered. Light soils are prepared with mature compost so that the water does not seep away too quickly. Radishes prefer evenly moist soil. The location should be sunny to semi-shady . In midsummer in particular, it is better to choose a semi-shaded location, as the plants will otherwise start to bolt. Shooting is when a radish grows upwards and forms flowers. In this case, the tuber becomes inedible.

Radish varieties: discover a broad variety

The variety now ranges from spherical to flat-round and elongated shapes in red, white, purple or yellow. Depending on the variety, radishes differ in their appearance and taste, but also in the best time to grow them.

Radishes are a big hit all year round, but you should always make sure you choose the right variety. Many varieties start to sprout and then flower if the temperature is too high. This is only desirable if you want to produce your own seeds. Most varieties have now been bred to be bolt-resistant. This means that the plants flower late or not at all. This is particularly advantageous for summer cultivation from May onwards. Varieties that are suitable for year-round cultivation include Sora, Topsi, French Breakfast and Eiszapfen.

Discover numerous varieties!

In our library you will find information on the individual radish varieties with cultivation periods, tips on planting and harvesting. You will also find good and bad neighbours to help you plan a mixed crop.

Discover library now

When to sow red radishes?

Red radishes are one of the first crops to open the gardening season. They can be sown directly outdoors from February/March until the beginning of September, or even as early as February if you have a greenhouse. Plant the seeds about 1 cm deep in the soil, 3 to 4 cm/1.2 to 1.6 in apart. Choose a distance of 10 to 15 cm/4 to 6 in between the rows. The seeds should not be sown deeper, otherwise they will form an elongated, woody tuber. You can make seed tapes for sowing radishes. You can find out how to make your own seed tapes in this article.

If you sow regularly, you can harvest your own fresh radishes right into the fall. In regions with late frosts, it is worth protecting the radishes with a fleece. It is also advisable to protect the seeds from birds until germination. Especially in early spring, the food supply is scarce and the local birds like to help themselves. The seeds should now germinate within a few days to a week with sufficient water. Depending on the variety, germination temperatures are between 6 - 15 °C/43 - 59 °F. As red radishes are cold germinators, germination is delayed at warmer soil temperatures. In midsummer, it can therefore be helpful to put the seeds in the fridge for about a week before sowing them.

German radishes in mixed cultivation: companion plants

Radishes have a particularly short cultivation period. Depending on the variety and time of year, it takes 4 to 8 weeks from sowing to harvest. For this reason, they can be used in a variety of ways. They are well suited as a pre-crop or post-crop and as an intercrop, but they can also be cultivated individually in pots. They are also often used as marker seeds to mark rows of slow-growing crops.

Table: Companion plants for red radishes

You can read more about mixed cultivation with cabbage here. As the red radish is not a heavy feeder like most cabbage plants, it is ideal for mixed cultivation with many plants.

Crop rotation with red radishes

Plants of the cruciferous family (Brassicaceae), including radishes, radishes, horseradish and various types of cabbage, should not be grown several times in succession in the same bed due to crop rotation. Give your bed a break of 3 years, otherwise you risk diseases. A crop rotation with peas, beans, lettuce or spinach would be better.

Your planting plan with garden radish

Radishes are a great gap filler and are also ideal as a starter crop. Here you can find some bed plans as an example of mixed cultivation with radishes. Have fun discovering them!

Planting radishes on the balcony

Radishes are perfect for growing in a pot or window box. Make sure there is enough space between the rows and plants so that the tubers can grow and thrive. The water must also be able to drain well, as radishes do not like waterlogging. After 4 to 8 weeks and daily watering, you can harvest your first radishes. You can find more ideas and inspiration for your balcony garden in this article.

Caring for garden radishes properly

• Especially at the beginning, you should ensure a sufficient and even water supply. If there is a lack of water or strong fluctuations, the tubers will become furry or may burst. Dryness also has a negative effect on the taste.
• Radishes are weak eaters and therefore do not need to be fertilized. An excess of nutrients will only make the plant more susceptible to diseases and pests. It also reacts with excessive leaf growth and too little tuber growth.

Diseases & pests of radishes

Due to their rapid growth, radishes are spared from many pests and diseases or harvested before larvae, viruses or germs develop. However, as part of the Brassicaceae family, radishes are on the menu of the cabbage fly and the cabbage whitefly. Slugs and snails also like the radish's tender cotyledons. A net helps to protect the plants. Earth fleas are also attracted to the seedlings, but can be kept away by watering evenly or using a layer of mulch. You can find out how to prevent and control plant pests such as cabbage white butterflies and slugs in this article.

Harvesting radishes

A radish is ready to harvest when it is 2 to 3 cm/0.8 to 1.2 in in diameter and can then be carefully pulled out of the soil.

When to harvest radishes?

As already mentioned, radishes only need 4 to 8 weeks to ripen. However, this only applies to long-day conditions, i.e. from March to September. In the fall, the days become shorter again. It can then take up to ten weeks before the radishes are ready to harvest. Don't wait too long to harvest, as some varieties then become furry or woody.

Storing radishes

Radishes are best stored in the fridge. However, all leaves should be removed beforehand. They draw moisture from the radishes and cause them to shrivel more quickly. It is best to store the radishes in an airtight tin. Wrapped in a damp kitchen towel, radishes will also keep for a few days. If they are already a little wrinkly, you can place the radishes in a bowl of cold water for 3 - 4 hours (or put the bowl of water in the fridge). This allows them to soak up the water again and become nice and crunchy.

Our tip: You can use the radish leaves to make a delicious pesto!

Obtaining radish seeds: here's how

If you like to produce your own seeds, you can easily do this with radishes. Simply leave your radish plant in the bed and let it continue to grow. It will then start to shoot and the tuber will become woody. A large number of white to purple flowers will form. Small pods eventually grow from them. These are edible when fresh and contain valuable proteins and nutrients. If you leave them to dry on the plant, they will produce ripe seeds for sowing the following year. Alternatively, you can leave the seeds to germinate and enjoy the valuable nutrients over the winter. You can find instructions on how to grow radish sprouts yourself in our article on the subject.

I hope I've whetted your appetite for growing radishes. If you have any questions or comments, please write to us at [email protected].

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Cover picture by Michaela Wenzler on Pixabay