When to plant radishes in District of Columbia
District of Columbia’s average last spring frost is April 10, and the first fall frost typically arrives around October 25 — about 198 frost-free days (USDA zones 7a, 7b, 8a). Radish needs 22–30 days to mature, which fits comfortably within District of Columbia's growing season.
When to plant radishes in District of Columbia: the short answer
For a spring planting, sow Mar 8 – Mar 27. Seeds germinate in soil from 40 to 85°F.
Succession sow again in District of Columbia: Mar 23 · Apr 2 · Apr 12 · Apr 22 · May 2 · May 12
Spring succession stops before summer heat makes it bolt. Start sowing again in late summer for a fall crop (see the fall window above).
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow radishes in District of Columbia, step by step
- Prepare the bed. They need six or more hours of sun for the best growth, though four to six hours in partial shade is enough and loose soil at least 6 inches deep, with a pH between 6.0 and 7.0. Dig in compost before planting.
- Sow outdoors (Mar 8 – Mar 27). Space plants about 2 inches apart in rows 6 inches apart, sowing seed ½ inch deep. It handles frost well, so it can go out before the last frost date. As a cool-season crop it does best before summer heat arrives in District of Columbia.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: flea beetle, cabbage root maggot, aphids. Diseases and disorders: clubroot, scab, downy mildew.
- Harvest (from about Apr 4 – Apr 12). Radish takes 22-30 days to reach harvest. 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.
Figures come from our crop data; dates use District of Columbia’s average frost dates. More in the full radish growing guide.
Radish planting dates by USDA zone in District of Columbia
District of Columbia spans USDA zones 7a, 7b, 8a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the radish dates shift with them.
When to plant radishes in nearby states
| State | Last frost | Sow |
|---|---|---|
| District of Columbia (this page) | April 10 | Mar 8 – Mar 27 |
| New Jersey | April 20 | Mar 18 – Apr 6 |
| Pennsylvania | May 1 | Mar 29 – Apr 17 |
| Delaware | April 14 | Mar 12 – Mar 31 |
| Maryland | April 14 | Mar 12 – Mar 31 |
| Virginia | April 15 | Mar 13 – Apr 1 |
| West Virginia | May 5 | Apr 2 – Apr 21 |
Questions gardeners in District of Columbia ask
When is the best time to plant radishes in District of Columbia?
Sow radishes in District of Columbia between March 8 and March 27. That timing is set by District of Columbia's average last spring frost of April 10.
Can I plant radishes in the fall in District of Columbia?
Yes. For a fall crop, sow between September 10 and September 27, so the crop matures in cool weather before District of Columbia's first frost around October 25.
When will radishes planted in District of Columbia be ready to harvest?
Planted on time, radishes are usually ready from about April 4 to April 12, 22-30 days after sowing.
When is the last frost in District of Columbia?
On average around April 10, with the first fall frost around October 25 - about 198 frost-free days. Your town may differ by two weeks or more.