How to grow radish
Raphanus sativus · Brassicaceae · Vegetable
When to plant radishes: the short answer
Sow outdoors about 4 weeks before the last frost; for a fall crop, sow about 5 weeks before your first fall frost. Seeds germinate in soil from 40 to 85°F, fastest near 70°F.
Cold winters (zone 5): sow Mar 28 – Apr 16, or sow Aug 21 – Sep 7 for a fall crop. Mild winters (zone 9): sow Oct 16 – Nov 2 for fall and winter harvests; the spring window (Jan 18 – Feb 6) closes before the summer heat. Skip the hottest months for radishes. See every zone.
Radish is a cool-season vegetable in the Brassicaceae family, almost always sown straight into the ground where it will grow. It wants full sun, though it tolerates a little afternoon shade in hot regions and steady, even moisture. From sowing to first pick is about 22–30 days. It handles frost well and a light freeze often improves the flavour.
Grower’s note: The classic marker crop and quick filler. Sow a short row every 10 days - a single big sowing all matures at once and then goes pithy and hot.
Sowing
Sow about 0.5″ deep, into soil between 40–85°F — germination is quickest near 70°F. It comes up fast (3–7 days). It does not transplant well, so sow it in its final position rather than starting it in pots.
Spacing & layout
Give each plant about 2″ along the row with roughly 6″ between rows. On a square-foot grid that is 16 per square foot. Allow at least 6″ of loose, workable soil for the roots. It grows well in containers at least 6″ deep.
Fitting it to your season
As a cool-season crop, radish does its best growing in the mild weather of spring and fall and tends to bolt or turn bitter in summer heat. A second sowing in late summer, timed to mature as the weather cools, is usually the better crop of the year — and light frost only sweetens it.
Quick facts
Growth stages: how long radishes take to grow
From sowing to first harvest takes roughly 22-30 days (3-4 weeks), with seedlings appearing after 3-7 days in soil around 70°F.
When to plant radish
When to plant radishes by USDA zone
Dates worked out from each zone’s typical frost dates for 2026. Find your zone on the zone map, or pick your state below for dates from its own frost dates. Zones 11 and above are frost-free, so timing there depends on heat and rain instead.
| Zone | Last / first frost | Start indoors | Sow or plant out | Fall or second sowing |
|---|---|---|---|---|
| Zone 3 | May 15 / Sep 15 | - | Apr 12 – May 1 | Aug 1 – Aug 18 |
| Zone 4 | May 10 / Sep 25 | - | Apr 7 – Apr 26 | Aug 11 – Aug 28 |
| Zone 5 | Apr 30 / Oct 5 | - | Mar 28 – Apr 16 | Aug 21 – Sep 7 |
| Zone 6 | Apr 15 / Oct 15 | - | Mar 13 – Apr 1 | Aug 31 – Sep 17 |
| Zone 7 | Apr 5 / Oct 25 | - | Mar 3 – Mar 22 | Sep 10 – Sep 27 |
| Zone 8 | Mar 20 / Nov 5 | - | Feb 15 – Mar 6 | Sep 21 – Oct 8 |
| Zone 9 | Feb 20 / Nov 30 | - | Jan 18 – Feb 6 | Oct 16 – Nov 2 |
| Zone 10 | Jan 30 / Dec 15 | - | Dec 28 – Jan 16 | Oct 31 – Nov 17 |
Or browse radish planting dates for every state as static pages.
Companions
Carrot, Lettuce, Cucumber, Pea, Spinach
No strong antagonists recorded.
Common problems
Pests: flea beetle, cabbage root maggot, aphids.
Diseases & disorders: clubroot, scab, downy mildew.
Same family (Brassicaceae)
Rotate these so they don’t follow each other in the same bed year to year.
Questions gardeners ask
When should I plant radishes?
Sow outdoors about 4 weeks before the last frost; for a fall crop, sow about 5 weeks before your first fall frost. Seeds germinate in soil from 40 to 85°F. The table on this page gives dates for each USDA zone, and the planting calendar gives dates for your own state or ZIP code.
How long do radishes take to grow?
About 22-30 days from sowing to the first harvest. Seeds germinate in 3-7 days, fastest in soil around 70°F.
How much sun do radishes need?
They need six or more hours of sun for the best growth, though four to six hours in partial shade is enough.
What soil pH do radishes need?
A soil pH between 6.0 and 7.0. Test before adding lime or sulfur - see the soil pH and testing guide.
How far apart should I plant radishes?
Space plants about 2 inches apart in rows 6 inches apart, or 16 per square foot in a square-foot bed. Sow seeds about ½ inch deep.
Can I grow radishes in a container?
Yes. Use a container at least 6 inches deep with drainage holes and a good potting mix, and water more often than you would in the ground.
Figures are typical home-garden ranges from Cooperative Extension planting guides, cross-checked against multiple state sources. Your variety and conditions will vary.