Topeka, Kansas: planting zone & frost dates
Topeka 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 20 and the first fall frost around Oct 17.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 27 | Oct 6 |
| Typical planning date (30% risk) | Apr 20 | Oct 17 |
| Median (50%) | Apr 16 | Oct 22 |
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 TOPEKA - NWS, KS (USC00148171), 4.4 mi (7.1 km) from the city center and 62 ft lower than the city center (-19 m). Record used for the 1991–2020 normals: 10 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Topeka
All 19 ZIP codes covering Topeka are in zone 6b.
Vegetable planting calendar for Topeka
Dates are counted from the 30%-risk frost dates above (last frost Apr 20, first frost Oct 17). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 23 – Mar 9 | Apr 27 – May 11 | — | — |
| Pepper | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Lettuce | Mar 9 – Mar 23 | Apr 6 – Apr 27 | Mar 23 – May 4 | Aug 8 – Sep 5 |
| Green Beans | — | — | Apr 27 – Jun 1 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | Apr 27 – May 25 | — |
| Zucchini & Summer Squash | Mar 23 – Mar 30 | Apr 27 – May 11 | Apr 27 – May 18 | Jul 25 – Aug 8 |
| Cucumber | Mar 23 – Mar 30 | May 4 – May 11 | Apr 27 – May 18 | Jul 25 – Aug 8 |
| Carrot | — | — | Mar 30 – May 4 | Jul 25 – Aug 8 |
| Onion | Jan 26 – Feb 9 | Mar 23 – Apr 6 | — | — |
| Potato | — | Mar 23 – Apr 13 | — | — |
| Basil | Mar 9 – Mar 23 | May 4 – May 18 | May 4 – May 25 | — |
| Spinach | — | — | Mar 9 – Apr 6 | Aug 22 – Sep 19 |
| Kale | Feb 23 – Mar 9 | Mar 23 – Apr 13 | Mar 23 – Apr 13 | Aug 8 – Sep 5 |
| Broccoli | Feb 23 – Mar 9 | Apr 6 – Apr 27 | — | Jul 25 – Aug 8 |
| Peas | — | — | Mar 9 – Mar 30 | Aug 8 – Aug 22 |
| Eggplant | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Cabbage | Feb 23 – Mar 9 | Mar 23 – Apr 6 | — | Jul 25 – Aug 8 |
| Radish | — | — | Mar 16 – May 4 | Sep 5 – Oct 3 |
| Strawberry | — | Mar 23 – Apr 13 | — | — |
| Beets | — | — | Mar 30 – May 11 | Aug 8 – Aug 22 |
Nearby cities in Kansas
- Lawrence — zone 6b, last frost Apr 17, first frost Oct 22
- Olathe — zone 6b, last frost Apr 16, first frost Oct 23
- Kansas City — zone 6b, last frost Apr 10, first frost Oct 29
- Overland Park — zone 6b, last frost Apr 16, first frost Oct 23
- Wichita — zone 7a, last frost Apr 16, first frost Oct 21
More: all Kansas cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Topeka gardening questions
When is the last frost in Topeka, KS?
Plan around Apr 20. At NOAA's Topeka - NWS, KS station, 4.4 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 16, and after Apr 27 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 5. The last frost is fairly predictable here: only 26 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Topeka, KS?
Start seeds indoors Feb 23 – Mar 9 and set transplants outside Apr 27 – May 11, once nights stay above 50°F and the soil is near 60°F. That leaves 180 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 Topeka?
About 189 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 169 days, and in 1 year in 10 it runs 209 days or more. In fall there is a 10% chance of frost by Oct 6 and a 30% chance by Oct 17. That is the shortest of the 6 Kansas cities on this site.
When should I plant a fall garden in Topeka?
Count back from the first fall frost (Oct 17): transplant broccoli Jul 25 – Aug 8; sow kale Aug 8 – Sep 5; sow lettuce Aug 8 – Sep 5; sow radishes Sep 5 – Oct 3. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 31. How the math works: succession and fall planting.
Did Topeka's hardiness zone change on the 2023 map?
Yes. Most of Topeka 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 Topeka compare with Lawrence, KS?
Both are in zone 6b. The typical last spring frost in Topeka (Apr 20) comes about the same time as in Lawrence, KS (Apr 17), 24 miles away, and the first fall frost is Oct 17 versus Oct 22. The two cities use different NOAA stations.