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When to plant radishes

Cabbage family, Raphanus sativus

Spacing
2″ apart
Per sq ft
16
To harvest
22–30 days
Frost
Hardy

Companion plants for radishes

What to grow next to radishes, what to keep away, and what is only tradition. Every pairing says how strong the evidence is.

Grow together 11

Helps, or shares the bed well.

  • Broccoli Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Broccoli guide

  • Cauliflower Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Cauliflower guide

  • Cabbage Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Cabbage guide

  • Kale Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Kale guide

  • Brussels sprouts Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Brussels sprouts guide

  • Bok choy Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Bok choy guide

  • Kohlrabi Studied Radish is a preferred food of flea beetles. Sown a little before the main crop, it draws them away from young cabbage and broccoli.

    Source: Brassica flea beetles, UMass Amherst Vegetable Program; Trap Cropping, Washington State University Extension Master Gardener Program. Kohlrabi guide

  • Pea Practical Fast radishes are harvested before the peas need the space.

    Pea guide

  • Carrot Practical Radishes sprout fast, mark the slow carrot row and break the soil crust for the carrots.

    Carrot guide

  • Lettuce Practical Radishes are pulled within a month, leaving room for the lettuce to fill out.

    Lettuce guide

  • Spinach Practical Both cool-season and quick; sow together in early spring.

    Spinach guide

Tradition only 5

On many charts, with little or no evidence.

  • Cucumber Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Cucumber guide

  • Zucchini Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Zucchini guide

  • Yellow squash Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Yellow squash guide

  • Winter squash Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Winter squash guide

  • Pumpkin Tradition Said to help Radishes are said to repel cucumber beetles. Studies have not shown it.

    Pumpkin guide

Studied Field or lab research shows an effect, at least under some conditions.
Mixed Some studies find an effect, others don’t, or it only works in a narrow way.
Practical Explained by light, space, timing, support or a shared pest or disease.
Tradition Widely repeated, but with little or no evidence behind it.

See every pairing side by side in the companion planting chart, or try them in a bed with the garden planner.

When to plant radishes by city

Sow radishes outdoors from 5 weeks before to 2 weeks after your last frost. For a fall crop, sow 4–6 weeks before your first fall frost. Here is what that means for 2027 in cities across the US, using each city’s average frost dates (NOAA 1991–2020). Pick the city with the climate most like yours, or enter your ZIP code above.

City Last frost Sow outdoors Fall crop
Seattle, WA (9a) Mar 13 Feb 6 – Mar 27 Oct 6–20
Portland, OR (8b) Feb 25 Jan 21 – Mar 11 Oct 20 – Nov 3
Sacramento, CA (9b) Jan 12 Dec 8 – Jan 26 Nov 4–18
Phoenix, AZ (10a) Jan 5 Dec 1 – Jan 19 Nov 22 – Dec 6
Salt Lake City, UT (7b) Mar 31 Feb 24 – Apr 14 Sep 27 – Oct 11
Denver, CO (6a) Apr 30 Mar 26 – May 14 Aug 31 – Sep 14
Dallas, TX (8b) Mar 2 Jan 26 – Mar 16 Oct 18 – Nov 1
Minneapolis, MN (5a) Apr 23 Mar 19 – May 7 Sep 4–18
Kansas City, MO (6b) Apr 4 Feb 28 – Apr 18 Sep 21 – Oct 5
Chicago, IL (6b) Apr 10 Mar 6 – Apr 24 Sep 24 – Oct 8
Columbus, OH (6b) Apr 20 Mar 16 – May 4 Sep 12–26
Nashville, TN (7b) Apr 1 Feb 25 – Apr 15 Sep 19 – Oct 3
Atlanta, GA (8a) Mar 24 Feb 17 – Apr 7 Sep 27 – Oct 11
Raleigh, NC (8a) Mar 28 Feb 21 – Apr 11 Sep 27 – Oct 11
Philadelphia, PA (7b) Mar 30 Feb 23 – Apr 13 Oct 6–20
Boston, MA (7a) Apr 4 Feb 28 – Apr 18 Sep 28 – Oct 12

In frost-free parts of Florida, southern California and the Gulf Coast, timing is about heat instead: grow radishes from fall through winter.

Radish spacing

In a square-foot bed, plant 16 per square foot. In traditional rows, space plants about 2 inches apart with 6 inches between rows.

Ready in a month. Sow a few every week instead of all at once.

One square foot planted with radishes, as drawn in the planner.

How to grow radishes

Radishes are the fastest crop in the garden, ready in about a month from seed. They are ideal for children and first-time gardeners, and for filling gaps between slower crops. The trick is sowing small amounts often and picking them before they turn pithy and hot.

Sun and soil

Full sun and loose, well-drained soil with a pH of about 6.0–7.0. Keep the soil evenly moist; fast, steady growth gives mild, crisp roots.

Planting

  1. Sow ½ inch deep as soon as the soil can be worked, about 5 weeks before the last frost, once soil is around 45°F.
  2. Thin seedlings to 2 inches apart in rows 6 inches apart. Crowded radishes grow leaves but no roots.
  3. Sow a short row every 7–10 days until about 2 weeks after the last frost, then stop until late summer.
  4. For fall radishes, sow again 4–6 weeks before the first fall frost.

Care

  • Water regularly. Dry soil followed by heavy watering splits roots and makes them hot.
  • Skip extra fertilizer in reasonably fertile soil; too much nitrogen gives tops instead of roots.
  • Radishes grow best below 80°F. Midsummer sowings tend to bolt or turn woody.
  • Pull weeds early; radishes compete poorly.

Harvest

Most round radishes are ready 3–4 weeks after sowing, when roots are about 1 inch across. Pull a test root to check. Do not leave them in the ground for long after they size up, because they quickly become pithy, split and sharp-tasting.

Common problems

  • Flea beetles: Small holes in seedling leaves. Cover the seedbed with row cover at sowing.
  • Root maggots: White maggots tunneling in roots. Row cover sealed at the edges keeps the flies from laying eggs; rotate where brassicas grew.
  • All tops, no roots: Caused by crowding, heat or shade. Thin promptly and sow in cool spring or fall weather.

Varieties to try

  • 'Cherry Belle' — round, red, very quick
  • 'French Breakfast' — oblong, red with white tip, mild
  • 'White Icicle' — long, white, mild
  • 'Easter Egg' — mix of red, purple, pink and white

Crop rotation

Radishes belong to the cabbage family (Brassicaceae). Clubroot and cabbage pests build up in the soil. Rotate for at least 3 years. Relatives that count as the same family for rotation: broccoli, cauliflower, cabbage, kale, brussels sprouts, turnip, arugula, bok choy, kohlrabi.

Frequently asked questions

When should I plant radishes?
Sow radishes outdoors from 5 weeks before to 2 weeks after your last frost. For a fall crop, sow 4–6 weeks before your first fall frost. Type your ZIP code above for exact dates, or see the city table.
What grows well with radishes?
Good neighbors for radishes include broccoli, cauliflower, cabbage, kale, brussels sprouts and bok choy. Each one is listed above with the reason and how strong the evidence is.
How far apart should I plant radishes?
In rows, space radishes about 2 inches apart with rows 6 inches apart. In a square-foot bed, plant 16 per square foot.
How long do radishes take to grow?
About 22–30 days from sowing to first harvest, depending on the variety and the weather.
Can radishes handle frost?
Yes. Radishes handle frost well and are planted before the last frost in spring and again for a fall harvest.

Sources

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When to plant

What grows together