How to grow radishes

Salad radishes are quick and easy to grow from seed, ready to eat in as little as four weeks. These compact plants can be grown in even the smallest of spaces and are great gap-fillers on the veg plot. Sow small batches every few weeks to add a crunchy kick to salads in late spring and summer. There are also winter cropping, oriental and edible-podded varieties. 

Radishes come in many shapes, sizes and colours, from small globes to long, tapering torpedoes, in shades of red, pink, white, yellow and even black-skinned.  

• Salad radishes (also known as spring or summer radishes) – these are the most popular and widely grown type of radish. They are small and fast growing, sown in the ground or in containers in spring and summer. There are many varieties, forming small succulent roots in a choice of shapes and colours. Great for eating raw, they are refreshing and crunchy with a peppery kick  

• Winter radishes – these hardy radishes are larger and slower growing, sown in late summer for harvesting from winter through to spring. If sown too early, they will bolt (start flowering) and the root won’t swell. They are mainly used in stews and stir-fries, in a similar way to turnips, and have a mild flavour when cooked  

• Oriental radishes (also known as Japanese, daikon or mooli radishes) – they usually form long white tapering roots that can be eaten raw or cooked. They are slow growing, often forming very long roots, and are usually harvested in late summer and autumn 

• Edible-podded radishes – these varieties are grown for their long spicy seed pods rather than their roots. They are extremely easy to grow and crop prolifically, especially in hot weather. Add the crisp, peppery immature pods to salads and stir-fries 

When choosing radish varieties, look in particular for those with an RHS Award of Garden Merit (AGM), which shows they performed well in trials – see our list of AGM fruit and veg.

For more veg-growing inspiration, visit the RHS gardens, which all grow a wide range of vegetables, including radishes, salads and other quick and easy crops.

Radishes are easy to grow from seed sown outdoors, either in the ground or in containers, and germination only takes 7–10 days.

Choose a sunny sowing site and prepare the ground by weeding, forking to loosen any compaction and raking to remove stones. Short-rooted salad radishes can also be sown in large containers, at least 30cm (1ft) wide and deep, filled with multi-purpose compost.

• Sow salad radishes in spring, early summer and late summer for best results. You can also sow in mid-summer in cooler locations or in light shade, out of midday sun. It is generally best to avoid sowing in hot dry weather, as plants tend to bolt (start flowering). For an early crop, sow in February in pre-warmed soil and protect with cloches. Sow seeds 1cm (½in) deep and 2.5–5cm (1–2in) apart, with 15cm (6in) between rows. Regular small sowings will provide continuous harvests – see our guide to successional sowing.

• Sow winter radishes in July or August, spacing seeds (or thinning seedlings) to 15–20cm (6–8in) apart, depending on the variety, with 15cm (6in) between rows. Long-rooted varieties need deep, fertile soil – some can reach 30cm (1ft) in length. The leaves grow up to 45cm (18in) tall and are edible too.

• Sow oriental radishes in spring and summer. Often called Japanese, daikon or mooli radishes, these usually have long white tapering roots, but some varieties are round or dark-skinned. Sow in a similar way to winter radishes, but over a longer period, and harvest before autumn frosts arrive.

• Sow radishes for edible pods in spring and summer. They do particularly well in hot weather, when radishes grown for roots would struggle. Sow seeds 1cm (½in) deep and 10cm (4in) apart. Sow several small batches for harvests over a long period.

Fast-growing salad radishes are ideal for filling any gaps on the veg plot or sowing between slower-growing crops such as peas and potatoes. They can also be used as row markers for slow-germinating crops, such as parsnips and onions – the radishes germinate quickly, marking out the row where the other crops have been sown, and are harvested before they can hinder the main crop’s growth.

Radishes are generally quick and easy to grow, but they do need regular water and warm but not overly hot temperatures, so the roots grow strongly and evenly. Make sure plants aren’t spaced too closely or crowded out by weeds.

Although radishes are generally easy and trouble free, especially spring sowings, you may get disappointing results if the growing conditions aren’t right, including: 

• Roots fail to swell – this can happen for various reasons, including dry conditions, heat and overcrowding. Salad radishes grow best in mild spring weather – in summer they need additional regular watering, especially in hot, dry spells. Make sure plants are well spaced – salad radishes at least 2.5cm (1in) apart, winter and oriental radishes 15cm (5in) apart – to give the leafy top-growth room to develop and swell the root. See our guide to watering vegetables.

• Flowering (or bolting) – this may happen in hot, dry weather, in which case the root won’t develop. Keep plants well watered over the summer and remove any that start to produce a flower stem (unless you want to harvest the edible seed pods) 

• Roots are woody, bitter or overly spicy – they are probably too old. Harvest salad radishes as soon as they reach about 2.5cm (1in) in diameter, which should only take about a month (or two months for early sowings) – don’t leave them much longer, as eating quality will suffer  

• Split roots – this is usually caused by uneven watering, so water during dry spells to ensure consistent growth. Split roots are usually still edible

A few pests can occasionally be problematic: 

• Slugs and snails - may eat seedlings, especially in damp conditions – see our tips on how to stop slugs and snails 

• Cabbage root fly larvae - may tunnel into the roots, especially in late summer. They are unlikely to trouble fast-growing salad radishes, but may cause problems with slower-growing winter and oriental types that are in the ground for longer – cover crops with fleece or insect-proof netting 

• Flea beetles - eat tiny holes in the leaves, but the damage is usually only cosmetic and doesn’t hinder growth