Brassica root
How to grow radishes
Raphanus sativus
Radishes are the fastest vegetable in the garden: sow a short row direct every two weeks from March to September and pull the roots four to six weeks later. They grow in any reasonable soil in sun or light shade, and in pots. The two things that decide quality are steady moisture and pulling on time, because a radish that dries out or sits too long turns hot, woody and hollow.
- Hardiness
- Hardy; winter types very hardy
- Position
- Full sun to light shade
- Soil
- Light, fertile, moist
- Ideal pH
- 6.5 to 7.0
- Water
- Moderate, even water keeps them mild
- Feeding
- Light feeder
Sowing and planting radishes
WhenSow Mar to Sep every 2 weeks; harvest 4 to 6 weeks later
Starting off
Direct every 2 weeks from March (under fleece) to September, germinating in 4 to 7 days at 10 to 20 °C; summer sowings need light shade and daily water. Sow winter radish in July to August. Not worth starting in modules; a quick row is always better.
Spacing and planting
Sow 1 cm deep in drills 15 cm apart and thin to 2 to 3 cm for summer types; winter types such as 'Black Spanish' at 15 cm in rows 30 cm apart. Perfect for a 15 cm deep pot, trough or windowbox, and as a marker row between slower crops.
Varieties worth growing
- French Breakfast 3
- Long, red root with a white tip; mild and crisp if pulled young. The classic for spring sowings.
- Cherry Belle
- Round, bright red and quick, and slower than most to go pithy if left a few days.
- Sparkler 3
- Round, red with a white base; reliable in pots and windowboxes.
- Black Spanish Round
- Winter radish with black skin and hot white flesh. Sow in July or August and lift from October for storing.
- April Cross F1
- Long white mooli for stir-fries and pickling. Sow from late June to August and lift in autumn.
Radishes month by month
Timings are for central England. Allow two weeks later in the north and on cold, heavy soil.
- January
Use winter radish from store or from under straw.
- February
Sow a first row under a cloche or in a cold greenhouse border at the end of the month.
- March
Sow outside under fleece. Sow a pinch of seed along the parsnip row as a marker.
- April
Sow every two weeks. Thin to 2 to 3 cm. Pull the first roots.
- May
Keep sowing, short rows only. Mesh against flea beetle. Water in dry spells.
- June
Sow in light shade between taller crops. Water daily in hot weather and pull promptly.
- July
Sow winter radish and mooli from mid July, thinning to 15 cm. Summer types bolt quickly now.
- August
Finish sowing winter types by mid August. Resume summer types as nights cool.
- September
Last sowing of summer radish in the first half of the month.
- October
Pull the last summer roots. Start lifting winter radish.
- November
Lift winter radish and store in damp sand, or cover the row with straw.
- December
Use stored winter radish. Order seed.
Feeding radishes
On soil that grew a fed crop last year, radishes need nothing at all. Nitrogen gives leaf at the expense of root, so feed only poor, sandy ground, and then lightly.
Low, too much nitrogen gives leaf, not root. On reasonable soil it needs almost nothing.
Feeding plan
Most soils
Nothing
No feed. The fertility left by the previous crop is enough for a four-week radish. Never sow on freshly manured ground.
Before sowing, poor or sandy soil only
Fruit & Vegetable Fertiliser 4-5-6
70 g/m², the bottom of the label range, raked in a week before sowing. For rows 15 cm apart that is about 10 g per metre of row.
Winter radish and mooli, every 2 to 3 weeks from thinning
1 g per litre of water over the row. It supplies trace elements with almost no nitrogen, which suits a root that is in the ground for three months.
Signs to watch
Woody, hollow or pithy roots
Dry soil and a crop left too long, never a feeding fault
Water daily and pull at 2 cm
Leafy plants with no swelling
Excess nitrogen or summer heat
Sow in cooler weather and never feed
Bolting straight to flower
Long midsummer days
Sow in spring and autumn
Pests, diseases and problems
Seedling leaves peppered with small round holes
Flea beetle, worst in warm, dry weather from April to August
Cover the row with fleece or fine insect mesh at sowing and keep the soil damp so the seedlings grow through it quickly. A well-watered row usually outgrows the damage.
Brown tunnels and white maggots in the roots
Cabbage root fly, which attacks all brassica roots
Fine mesh over the row from sowing, with the edges buried. Do not leave old radishes standing, as they keep the fly breeding.
Ragged holes in the leaves and scarred, gnawed roots
Slugs and snails
Pull the crop promptly, water in the morning not the evening, and patrol with a torch after rain.
Roots split open
A heavy watering or rain after the soil has dried out
Water lightly and often in dry spells so the soil never dries completely, and pull as soon as the roots are ready.
Winter radish wilts on sunny days and the root is swollen and distorted
Clubroot, a soil-borne disease of the brassica family
Keep winter types within the brassica rotation, improve drainage and lime to pH 7 if a test shows the soil is acid. Summer radish is rarely in the ground long enough to suffer.
Harvest and rotation
Harvest and storage
Pull summer types at 2 to 3 cm across, 4 to 6 weeks from sowing, before they turn hot and hollow; winter radish at 10 to 15 cm across in October to November. A 1 m row gives 40 to 60 roots. Summer radish keeps a week in the fridge; winter types store in damp sand until February or stand in the ground under straw.
Rotation and companions
Rotation: brassica group, but a 4 to 6 week crop that is usually ignored in rotation plans. Sow with carrots and parsnips to mark the rows and loosen the soil; lettuce alongside gives useful summer shade.
Good to knowSow little and often; harvest promptly before they turn hot and pithy.
Growing radishes in pots
Radishes are one of the best crops for a pot. Any container 15 cm deep will do for round and French Breakfast types: a trough, a windowbox or a 25 cm pot. Fill with multipurpose compost, fresh or reused from a previous crop, with no added fertiliser, and scatter the seed thinly so the plants stand 2 to 3 cm apart. Keep the compost moist every day, since a pot that dries out gives hot, woody roots. In June and July move the pot to a spot that gets afternoon shade. Sow a new pot every fortnight.
Radishes: common questions
Why are my radishes all leaf and no root?
Too much nitrogen, too little light or too little space are the usual causes. Seedlings left unthinned or sown in deep shade make tops but never swell, and so do plants on freshly manured or heavily fed soil. Thin to 2 to 3 cm, sow in an open spot, do not feed, and avoid midsummer sowings, which run to flower in long days.
How long do radishes take to grow?
Summer radishes are ready four to six weeks after sowing, as little as three and a half weeks in warm, moist soil in May. Winter radishes and mooli take 10 to 12 weeks from a July or August sowing.
Why are my radishes so hot and woody?
They have been short of water or left in the ground too long. Heat builds as the root ages and as the soil dries. Water every day in dry weather, pull at 2 to 3 cm across, and sow little and often so there is always a young row coming on.
Sources
Growing information on this page was checked against these references in November 2026. Feeding rates are Dr Forest label rates.