Parma, Ohio: planting zone & frost dates
Parma is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around Apr 27 and the first fall frost around Oct 30.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 5 | Oct 21 |
| Typical planning date (30% risk) | Apr 27 | Oct 30 |
| Median (50%) | Apr 20 | Nov 3 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station CLEVELAND, OH (USW00014820), 7.1 mi (11.4 km) from the city center and 180 ft lower than the city center (-55 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Parma
All 3 ZIP codes covering Parma are in zone 6b.
Vegetable planting calendar for Parma
Dates are counted from the 30%-risk frost dates above (last frost Apr 27, first frost Oct 30). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 2 – Mar 16 | May 4 – May 18 | — | — |
| Pepper | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Lettuce | Mar 16 – Mar 30 | Apr 13 – May 4 | Mar 30 – May 11 | Aug 21 – Sep 18 |
| Green Beans | — | — | May 4 – Jun 8 | Aug 7 – Aug 21 |
| Sweet Corn | — | — | May 4 – Jun 1 | — |
| Zucchini & Summer Squash | Mar 30 – Apr 6 | May 4 – May 18 | May 4 – May 25 | Aug 7 – Aug 21 |
| Cucumber | Mar 30 – Apr 6 | May 11 – May 18 | May 4 – May 25 | Aug 7 – Aug 21 |
| Carrot | — | — | Apr 6 – May 11 | Aug 7 – Aug 21 |
| Onion | Feb 2 – Feb 16 | Mar 30 – Apr 13 | — | — |
| Potato | — | Mar 30 – Apr 20 | — | — |
| Basil | Mar 16 – Mar 30 | May 11 – May 25 | May 11 – Jun 1 | — |
| Spinach | — | — | Mar 16 – Apr 13 | Sep 4 – Oct 2 |
| Kale | Mar 2 – Mar 16 | Mar 30 – Apr 20 | Mar 30 – Apr 20 | Aug 21 – Sep 18 |
| Broccoli | Mar 2 – Mar 16 | Apr 13 – May 4 | — | Aug 7 – Aug 21 |
| Peas | — | — | Mar 16 – Apr 6 | Aug 21 – Sep 4 |
| Eggplant | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Cabbage | Mar 2 – Mar 16 | Mar 30 – Apr 13 | — | Aug 7 – Aug 21 |
| Radish | — | — | Mar 23 – May 11 | Sep 18 – Oct 16 |
| Strawberry | — | Mar 30 – Apr 20 | — | — |
| Beets | — | — | Apr 6 – May 18 | Aug 21 – Sep 4 |
Nearby cities in Ohio
- Cleveland — zone 7a, last frost Apr 14, first frost Nov 7
- Akron — zone 6b, last frost Apr 30, first frost Oct 22
- Toledo — zone 6b, last frost Apr 27, first frost Oct 22
- Columbus — zone 6b, last frost Apr 27, first frost Oct 20
- Dayton — zone 6b, last frost Apr 25, first frost Oct 21
- Cincinnati — zone 6b, last frost Apr 24, first frost Oct 21
More: all Ohio cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Parma gardening questions
When is the last frost in Parma, OH?
Plan around Apr 27. At NOAA's Cleveland, OH station, 7.1 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 20, and after May 5 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 5. The 90% and 10% dates are 31 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Parma, OH?
Start seeds indoors Mar 2 – Mar 16 and set transplants outside May 4 – May 18, once nights stay above 50°F and the soil is near 60°F. That leaves 186 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Parma?
About 198 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 175 days, and in 1 year in 10 it runs 217 days or more. In fall there is a 10% chance of frost by Oct 21 and a 30% chance by Oct 30. That ranks 2nd longest of 7 Ohio cities on this site.
When should I plant a fall garden in Parma?
Count back from the first fall frost (Oct 30): transplant broccoli Aug 7 – Aug 21; sow kale Aug 21 – Sep 18; sow lettuce Aug 21 – Sep 18; sow radishes Sep 18 – Oct 16. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 13. How the math works: succession and fall planting.
Did Parma's hardiness zone change on the 2023 map?
Yes. Most of Parma was zone 6a on the 2012 map and is zone 6b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Parma compare with Cleveland, OH?
Parma is zone 6b and Cleveland is zone 7a. The typical last spring frost in Parma (Apr 27) comes about 13 days later than in Cleveland, OH (Apr 14), 7 miles away, and the first fall frost is Oct 30 versus Nov 7. Parma sits about 312 ft higher, which explains part of the gap. The two cities use different NOAA stations.