In zone 6, sow radishes from April 3 to April 17, two to four weeks before your last spring frost, and keep sowing short rows every 10–14 days for a steady supply. They are ready in about 25–30 days. For fall, the last sowing date is about September 1.
Radish dates for your ZIP code
Planting times based on university extension guidance (UNH, Cornell, Purdue, Minnesota, Nebraska and UMass Extension). Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Radish timing in zone 6
| Task | When |
|---|---|
| Sow outside | April 3 – April 17 |
| First harvest | April 28 – May 17 |
| Sow for fall by | September 1 |
| Sow again | Every 10–14 days in spring and late summer |
| Sow winter radishes | Midsummer to late summer |
| Pick | When roots are under 1 inch across |
Most of zone 6 sees its last spring frost between April 25 and May 8 (typical May 1) and its first fall frost between October 7 and October 18 (typical October 13). Radishes tolerate frost and grow fast in cool weather. The tool above uses the weather station closest to your ZIP code.
Why radishes are sown early
Radishes are a fast, cool-season crop that tolerates frost. In cool weather they grow quickly and stay crisp and mild. Heat and slow growth make them hot, pithy and quick to send up seed stalks. That is why they are sown two to four weeks before the last spring frost, and again in late summer.
Best radish varieties for zone 6
In zone 6, radishes have a spring and a fall season, with a break in summer heat.
- Spring radishes, round or oval, for spring and fall sowings.
- French Breakfast and Icicle, which tolerate warmer weather.
- Winter radishes such as daikon and black radish, sown in summer for fall.
How to plant radishes
- Sow seeds ¼–½ inch deep directly in the garden.
- Thin spring radishes to ½–1 inch apart, and winter radishes to 2–4 inches.
- Sow a short row every 10–14 days for a steady harvest.
- Keep the soil evenly moist so roots grow fast and don’t split.
Zone 6 radish tips
- Skip midsummer. Heat makes radishes hot, pithy and quick to send up seed stalks.
- Sow again in late summer so the roots mature in cool fall weather.
- Water evenly. Uneven moisture splits the roots.
- Harvest on time. Radishes go from perfect to pithy in days. Check them often.
Harvesting radishes
Pull spring radishes when the roots are under about an inch across, usually 25–30 days after sowing. Check them often, because they turn pithy and hot quickly once mature. Remove the greens before storing; radishes keep 5–7 days in the refrigerator. Winter radishes can stay in the garden into fall and keep for months in cold storage.
Radish planting dates in nearby zones
See dates for every zone on the radishes planting guide, or build a full schedule with the planting calendar.
Frequently asked questions
Is it too late to plant radishes in zone 6 in May?
For spring, yes: radishes maturing in summer heat turn hot and pithy. Sow again in late summer, by about September 1.
Why are my radishes hot or spongy?
They grew slowly or stayed in the ground too long. Heat and age make radishes hot and pithy. Sow in cool weather and harvest young.
How long do radishes take to grow?
Spring radishes are ready in about 25–30 days. Winter radishes such as daikon take longer and grow much larger.
Can radishes handle frost?
Yes. Radishes are frost tolerant and are sown two to four weeks before your last spring frost.
Why are my radishes all leaves and no root?
Usually crowding or heat. Thin seedlings to at least ½–1 inch apart, and sow in cool weather.
Sources. Planting dates use the median frost dates of each USDA zone, calculated from NOAA climate data for every ZIP code in the zone.