When to plant radishes in Pennsylvania
Pennsylvania’s average last spring frost is May 1, and the first fall frost typically arrives around October 10 — about 162 frost-free days (USDA zones 5a, 5b, 6a, 6b, 7a, 7b). Radish needs 22–30 days to mature, which fits comfortably within Pennsylvania's growing season.
Pennsylvania covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant radishes in Pennsylvania: the short answer
For a spring planting, sow Mar 29 – Apr 17. Seeds germinate in soil from 40 to 85°F.
Succession sow again in Pennsylvania: Apr 13 · Apr 23 · May 3 · May 13 · May 23 · Jun 2
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 Pennsylvania, 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 29 – Apr 17). 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 Pennsylvania.
- 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 25 – May 3). 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 Pennsylvania’s average frost dates. More in the full radish growing guide.
Radish planting dates by USDA zone in Pennsylvania
Pennsylvania spans USDA zones 5a, 5b, 6a, 6b, 7a, 7b. 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 |
|---|---|---|
| Pennsylvania (this page) | May 1 | Mar 29 – Apr 17 |
| New Jersey | April 20 | Mar 18 – Apr 6 |
| Delaware | April 14 | Mar 12 – Mar 31 |
| Maryland | April 14 | Mar 12 – Mar 31 |
| District of Columbia | April 10 | Mar 8 – Mar 27 |
| Virginia | April 15 | Mar 13 – Apr 1 |
| West Virginia | May 5 | Apr 2 – Apr 21 |
Questions gardeners in Pennsylvania ask
When is the best time to plant radishes in Pennsylvania?
Sow radishes in Pennsylvania between March 29 and April 17. That timing is set by Pennsylvania's average last spring frost of May 1; Pennsylvania spans several climates, so cooler and higher parts of the state run later.
Can I plant radishes in the fall in Pennsylvania?
Yes. For a fall crop, sow between August 26 and September 12, so the crop matures in cool weather before Pennsylvania's first frost around October 10.
When will radishes planted in Pennsylvania be ready to harvest?
Planted on time, radishes are usually ready from about April 25 to May 3, 22-30 days after sowing.
When is the last frost in Pennsylvania?
On average around May 1, with the first fall frost around October 10 - about 162 frost-free days. Your town may differ by two weeks or more.