Growing radishes: sowing, location & the right soil
Radish cultivation is pretty straight-forward. We will tell you what you should pay attention to when planting and sowing radishes.
Radishes are at the top of the list of the most popular vegetables in summer. Whether in salads, on bread or made into a dip – the crunchy, mildly spicy tubers are a must. They are also extremely healthy due to the vitamins, mustard oils and minerals they contain.
The radish (Raphanus sativus var. sativus) belongs to the genus Raphanus in the crucifer family (Brassicaceae). Originally, radishes come from Asia. These crunchy vegetables have been common in Europe since the 16th century. Radish cultivation in the garden is easy yet extremely rewarding, especially in temperate climatic conditions. Good news for those without a garden: radishes can just as easily be grown on the balcony. Only a few weeks after sowing, the small, mostly red tubers are ready for harvest. Due to the short cultivation period of about four weeks, radishes can be grown as a preceding or subsequent crop, as well as an intermediate crop between other types of vegetables in crop rotation.
Tip: Radishes work great as a catch crop, but not between other cruciferous plants. Do not plant radishes, horseradishes and different types of cabbage several times in a row in the same bed, as this can lead to various plant diseases, such as cabbage hernia. Radishes can be combined very well with peas, beans, lettuce or spinach in crop rotation.
There is a wide range of radish varieties, which differ not only in their cultivation time but also in their colour, shape and taste. In the rounded or flat-on-top varieties, the tuber is formed from the hypocotyl, i.e. the root neck. Elongated varieties of radishes include the root as well as the root neck in their storage organ, which makes the shape of the radish longer.
Planting radishes: location & soil
Radishes prefer a sunny to semi-shady location. Especially when growing in midsummer, it is better to choose a spot in partial shade, as otherwise the radishes tend to shoot excessively. Radishes grow in all normal garden soils. For the delicate tubers to grow well, however, the soil should be loose, humus-rich and ideally evenly moist. Before growing radishes, you should not apply heavy, and certainly not mineral fertiliser, because radishes are light feeders. You can tell that the soil is too nutritious for them with increased susceptibility to diseases and pests, excessive leaf growth and fewer tubers.
If your soil stores nutrients rather poorly (which is the case with sandy soils, for example) it can be helpful to fertilise radishes organically. Vegetable beds with heavy and rather dense soil should be loosened up a little before planting radishes, so that the tubers can grow downwards unhindered. Peat-free potting soil is very suitable for growing radishes in pots on the terrace or balcony.
Tip: When a radish plant starts to form flowers and grows tautly upwards, this is called shooting. If you want to harvest seeds, this is what you should watch out for. If you want to eat the tuber, however, shooting is not what you want because it removes water and storage substances from the tuber, making it dry and inedible.
Sowing radish seeds is easy and can take place almost the entire garden year. In the following, we will provide you with detailed instructions on how to sow radishes.
When to sow radishes?
Radishes are one of the earliest vegetable crops of the year. Radishes can be sown in frost-protected conditions at the end of February (under transparent plastic sheets or in heated garden beds). However, the best time to plant radishes is March. Until mid-April it is wise to keep garden fleece ready to cover the garden bed in very late frost-prone areas. From March to the beginning of September you can sow radishes continuously on a weekly basis. In this way, you can enjoy your own freshly grown radishes from the beginning of May until October. But beware: not all varieties grow well at all times of the year, some shoot directly in warm temperatures without forming a tuber at all. For this reason, always choose the right radish variety depending on the season.
How to sow radishes?
After preparing the soil, radish seeds can be sown. First, make shallow furrows for the seeds using a stick or the back of a garden rake. This step will help you place the seeds as straight as possible in a row.
The sowing depth for radishes is one centimetre. If the radishes are sown too deep, an elongated, woody tuber will form. The best way to sow radishes is in a row. Some of you might be wondering how far apart to plant radishes. The ideal distance between the radish seeds is three to four centimetres apart. A distance of 10 to 15 centimetres should be kept between the rows. Then, cover the seeds lightly with some soil. Next, press the soil lightly so that the seeds are not dispersed by rain or wind. At temperatures around 15°C and with an adequate water supply, the seeds will germinate within a few days.
As an alternative to the somewhat laborious individual placement of the radish seeds, the seeds can also be scattered directly from the bag. However, in this way radishes are usually sown too densely. The result is that no nice round root tubers develop. The radishes remain small and elongated and shoot faster. To avoid this, the densely sown radishes must be pricked, i.e. separated, shortly after seedlings emerge from the ground. This is done by carefully pulling the seedlings out of the soil with some pincers or by hand, carefully separating their roots and then replanting them at a greater distance.
Tip: Radishes are among the fastest growing seeds in the garden. This is why they are often used as “marking seeds”. Slow-germinating plants such as carrots are often accidentally sown over again because the seeds simply do not germinate for weeks. Those who have sown the fast-growing radishes on the left and right will remember that carrots should still be able to grow in the narrow strip in between.
Planting radishes in a pot
Growing radishes in a pot is a possibility for those who do not own a garden. Radishes can also be easily cultivated on the balcony in the flower box. Depending on how many rows you want to sow, you should choose a pot that is large enough to allow the necessary ten-centimetre row spacing. There should also be a drain hole so that excess water can run off when watering. Fill the pot with potting soil to about 15 centimetres in height. After that the radish seeds can be sown as described above.
Summary: planting radishes
- Sowing: early March to early September
- Garden bed preparation: rake it through and make holes for the seeds
- For early sowing: protect seeds or seedlings from late frost with garden fleece or plastic cover
- Sowing depth: 1 cm
- Distance in the row: 3 – 4 cm
- Distance between rows: 15 cm
- Cover the radish seeds with a thin layer of soil and press them lightly
- Water them daily
Care for radishes after planting
After sowing radishes, the seedlings must be regularly supplied with water. Strong fluctuations in watering will result in underdeveloped or burst tubers. If regular watering is ensured, large and crunchy radishes can be harvested after four to eight weeks. When watering, use a watering attachment through which the water is finely distributed. Without an attachment, there is a risk that the freshly sown seeds will be washed away or the seedlings damaged.