Raphanus sativus

Radish is one of the fastest crops you can put in the ground, ready in as little as four weeks, with a slower winter form that carries the season on past the point where the quick summer type finishes.

Summer radish rewards speed and small, repeated sowings; winter radish rewards patience and a narrow sowing window. Treat them as two different crops sharing a name rather than one crop grown two ways. In Scotland a cool summer helps, since hot, dry weather is what sends summer radish to flower.

Sowing summer radish

Sow from February under clochesA small, portable clear cover placed over an individual plant or short row to trap warmth and keep off wind, rain and pests. Full definition →, then spring to September, in small batches every few weeks rather than one row, about 1cm deep, thinning to 2.5-5cm apart in rows 15cm apart. Avoid sowing into the hottest, driest stretch of summer if you can help it. An early crop from February is possible with pre-warmed soil and a cloche.

Planting CalendarKeep radish sowings coming little and oftenPlan a run of small, staggered sowings rather than one big batch.
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Sowing winter radish: a different plant, a different window

Sow July or August only, about 2cm deep: earlier and the plant boltsA plant switching early into flowering and seed production, usually triggered by stress, after which leaves, roots or bulbs turn bitter or unusable. Full page → and the root won't swell. Space plants 15-20cm apart in rows 15cm apart, considerably more room than summer radish needs. It's a slower crop, taking 8-12 weeks (Teagasc gives 8-10, Garden Organic 10-12) against the summer type's 4-8, and it pays that time back by staying usable through winter.

Varieties

Scarlet Globe (red globe-shaped roots with white flesh) and French Breakfast 4 Francis (red cylindrical roots with a white tip) also hold the AGMThe RHS's Award of Garden Merit: a UK-wide trials award for reliable performance, not a Scotland-specific recommendation. Full definition →, a UK-wide award rather than a Scottish one. China Rose is a winter type without one. Oriental mooli and edible-podded radishes are separate, less common types.

★ Our pick for Scotland

AmethystAGM

Salad radish, purple roots, slow to turn woody

Purple roots with crisp white flesh.

Why this one: An AGM salad radish with purple roots and crisp white flesh. Radish punishes hesitation more than most quick crops, since roots left too long turn woody and bitter, so sow little and often.

Also worth considering

Black Spanish Round

Winter radish, sow July/August

A winter radish with black skin and sharp-flavoured white flesh, sown in July or August for lifting from November, through the months the summer type can't reach.

Best Radish Varieties for Scotland → compares all named radish varieties head-to-head, with the practical detail that doesn't fit in a summary card.

Watering and care

Keep the soil consistently moist rather than heavily watered. Too much water produces lots of leaf and small roots, and roots that lack water may fail to swell, so even, moderate moisture beats generous watering. Uneven moisture is also what causes split roots, usually still edible but worth avoiding with regular watering through dry spells. Weed by hand close to the plants rather than hoeing, to avoid disturbing the root. Radish grows best in soil of about pH 6.0 to 6.8 (UMass Amherst Extension).

Intercropping with radish

Radish's speed is useful beyond its own harvest. Sown into the gaps between young, slow-growing crops such as Brussels sprouts or sweetcorn, it's harvested and gone before the bigger plants need the space or start shading it out.

Radish seedlings sown in the gaps between young Brussels sprouts plants, ready to harvest before the bigger plants need the space
Radish sown between young Brussels sprouts, harvested before the bigger plants need the room.

Harvesting

Pull summer radish young, at about 2.5cm across: waiting longer makes it worse, as roots turn woody, bitter and overly spicy. Winter radish can stay in the ground and be dug as needed, protected in freezing weather with a cloche or fleeceA lightweight, breathable fabric laid or draped over plants to trap a little warmth and keep off frost, wind and some flying pests. Full definition →, or be lifted from November and kept somewhere cool such as the fridge.

A hand lifting a winter radish root from under a cloche in late autumn, other roots left in the ground
Winter radish lifted from under a cloche as needed.

Common problems

  • Slugs and snails attack young seedlings, especially in damp conditions.
  • Woody, pithy roots mean the crop was left too long. Harvest summer radish at about 2.5cm across, without waiting for it to get bigger.
  • Roots that stay small or fail to swell usually come down to overcrowding or a dry spell. Thin properly and keep the soil evenly moist.
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  • Bolting is triggered by hot, dry weather on summer radish, and by sowing too early on winter radish. Remove plants that send up flower stems unless you want the seed pods.
  • Split roots are caused by uneven watering, a dry spell followed by heavy rain or a sudden soak. Usually still edible.
  • Flea beetles leave small holes in the leaves, but the damage is usually only cosmetic.
  • Cabbage root fly larvae tunnel into the roots, mainly of the slower winter and oriental types. Fleece or insect-proof netting protects them.
  • Club root and brassicaThe cabbage family: cabbage, kale, broccoli, cauliflower, Brussels sprouts, kohlrabi, swede, turnip and more, sharing the same pests, diseases and rotation rules. Full definition → downy mildew can both affect radish, since it's a brassica itself. Include it in your brassica rotationMoving each crop family to different ground each year, on a multi-year cycle, so pests and diseases that build up in soil don't get a repeat host. Full definition → rather than treating it as exempt because it's fast.
  • Rhizoctonia root rot is named as a radish disease by Teagasc, and root rot can follow waterlogging. Good drainage and avoiding overwatering are the main defences.
Garden MythsWhat's true about growing radish?Every common claim checked: what holds up, what the sources argue over, and what has been tested and found false.
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Common questions

Should I water radish generously to get a bigger crop?

No: too much water produces lots of leaf and small roots (Garden Organic), while roots that lack water may fail to swell. Keep the soil consistently moist, especially in dry spells. See also: Radish Myths →

Can I sow winter radish any time, the way I can with summer radish?

No: winter radish is sown in July or August; sown too early it bolts and the root won't swell. See also: Radish Myths →

Is radish only worth growing in summer?

No: a winter radish sown in July or August is lifted from November and, with some protection, stays usable well into winter. See also: Radish Myths →

Can I plant radish between my other vegetables to save space?

Yes: radish is fast enough to sow between slower-growing crops such as Brussels sprouts or sweetcorn and harvest before the bigger plants need the room. See also: Radish Myths →

Sources

Show the 5 sources
  • RHS: the four radish types, soil prep, sowing depth and timing for summer and winter radish, spacing, watering, weeding, harvest timing and size, bolting cause and fix, split-root cause, seven named varieties with exact AGM status, pest and disease list
  • Garden Organic: corroborates the growing calendar and harvest-young advice independently; gives a shallower sowing depth (0.5cm) than the RHS; a specific overwatering caution (too much water produces lots of leaves and small roots); winter radish 10-12 weeks
  • Teagasc: corroborates sowing windows, spacing and harvest timing independently for both summer and winter radish; winter radish 8-10 weeks and summer 4-8 weeks; Rhizoctonia root rot as a named disease
  • BBC Gardeners' World: independently corroborates radish as a fast intercrop between slower-maturing vegetables
  • nevegetable.org: Soil pH 6.0 to 6.8