Radishes
Radishes are quick, easy and fun to grow from seed, ready to eat in as little as four weeks. These compact plants can be grown in even the smallest of gardens and are great gap-fillers on the veg plot. Sow small batches every few weeks for harvesting throughout summer, to add a crunchy tang to your salads. There are even varieties for winter cropping.
Jobs to do now
- Sow seeds in small batches
- Water regularly
- Harvest
Month by month
Sow
It’s best to sow radish seeds little and often, for small but continuous harvests. Aim to provide consistent conditions to ensure they grow well without any checks to their growth.
Sow outdoors, in the spot where they’re to grow. This can be in the ground, in containers or even in a growing bag. Sow seeds in short drills, 1cm (½in) deep and about 2.5cm (1in) apart.
For an early crop, sow in February into pre-warmed soil and protect with cloches.
Sow summer cultivars from March to mid-August.
Winter cultivars should be sown in July or August – space seeds 23cm (9in) apart to minimise the need for thinning later on. If sowing more than one row, keep them 15cm (6in) apart.
Grow
Thinning shouldn’t be necessary if you sow summer cultivars 2.5cm (1in) apart and winter cultivars 15cm (5in) apart. If thinning is required, do it as soon as possible.
Keep the soil moist to ensure rapid growth, for fleshy, tasty roots that don’t split. This can be tricky in hot dry summer weather, so take care to water regularly.
Because radishes are quick to mature, they can be sown as a ‘catch crop’ between rows of slower-growing vegetables such as peas and potatoes.
They can even be used as row markers for slow-germinating crops, such as parsnip 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.
Harvesting
Summer radishes are best harvested young, in as little as four weeks from germination, when the roots are about 2.5cm (1in) in diameter. If left to grow too large, they can become woody and inedible.
Pull as required, and eat fresh, when crunchy and delicious.
Winter radishes can be left in the ground and dug up as required, or lifted in November and stored.
Recommended Varieties
Radishes — summer & autumn
'French Breakfast 3'
'Scarlet Globe' AGM
‘Sparkler’ AGM
Radishes — winter
'Mooli'
‘Black Spanish’ AGM
China Rose
Common problems
Flea beetle
Leaves are covered in small holes and damaged areas turn brown. Seedlings are particularly susceptible.
Remedy
Grow plants under horticultural fleece and keep the soil moist. Water in nitrogen-rich fertilser to help the crop outgrow the pest.
Slugs and snails
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These feed on the young seedlings and you'll see the tell tale slime trail on the soil around your crop, as well as on the leaves.
Remedy
There are many ways to control slugs and snails, including beer traps, sawdust or eggshell barriers, copper tape and biocontrols.
Brassica downy mildew
This is a common disease of brassicas, as they are not in the ground so long. The leaves will turn yellow, with white, fuzzy patches on the undersides. The root may also turn brown.
Remedy
Remove infected plants as soon as you see them. Don’t plant brassicas in the same place as previous brassica crops.
Recipes
Nigel Slater suggests a radish, mint and feta salad for a summer lunch full of freshness and vitality.
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.