Conroe, Texas: planting zone & frost dates
Conroe is in USDA plant hardiness zone 9a, where the average coldest winter night reaches 20 to 25°F (-6.7 to -3.9°C). The typical last spring frost is around Mar 4 and the first fall frost around Nov 24.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Mar 17 | Nov 11 |
| Typical planning date (30% risk) | Mar 4 | Nov 24 |
| Median (50%) | Feb 24 | Dec 2 |
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 CONROE, TX (USC00411956), 0.1 mi (0.2 km) from the city center and 20 ft higher than the city center (+6 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Conroe
All 10 ZIP codes covering Conroe are in zone 9a.
Vegetable planting calendar for Conroe
Dates are counted from the 30%-risk frost dates above (last frost Mar 4, first frost Nov 24). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Jan 7 – Jan 21 | Mar 11 – Mar 25 | — | — |
| Pepper | Dec 24 – Jan 7 | Mar 18 – Apr 1 | — | — |
| Lettuce | Jan 21 – Feb 4 | Feb 18 – Mar 11 | Feb 4 – Mar 18 | Sep 15 – Oct 13 |
| Green Beans | — | — | Mar 11 – Apr 15 | Sep 1 – Sep 15 |
| Sweet Corn | — | — | Mar 11 – Apr 8 | — |
| Zucchini & Summer Squash | Feb 4 – Feb 11 | Mar 11 – Mar 25 | Mar 11 – Apr 1 | Sep 1 – Sep 15 |
| Cucumber | Feb 4 – Feb 11 | Mar 18 – Mar 25 | Mar 11 – Apr 1 | Sep 1 – Sep 15 |
| Carrot | — | — | Feb 11 – Mar 18 | Sep 1 – Sep 15 |
| Onion | Dec 10 – Dec 24 | Feb 4 – Feb 18 | — | — |
| Potato | — | Feb 4 – Feb 25 | — | — |
| Basil | Jan 21 – Feb 4 | Mar 18 – Apr 1 | Mar 18 – Apr 8 | — |
| Spinach | — | — | Jan 21 – Feb 18 | Sep 29 – Oct 27 |
| Kale | Jan 7 – Jan 21 | Feb 4 – Feb 25 | Feb 4 – Feb 25 | Sep 15 – Oct 13 |
| Broccoli | Jan 7 – Jan 21 | Feb 18 – Mar 11 | — | Sep 1 – Sep 15 |
| Peas | — | — | Jan 21 – Feb 11 | Sep 15 – Sep 29 |
| Eggplant | Dec 24 – Jan 7 | Mar 18 – Apr 1 | — | — |
| Cabbage | Jan 7 – Jan 21 | Feb 4 – Feb 18 | — | Sep 1 – Sep 15 |
| Radish | — | — | Jan 28 – Mar 18 | Oct 13 – Nov 10 |
| Strawberry | — | Feb 4 – Feb 25 | — | — |
| Beets | — | — | Feb 11 – Mar 25 | Sep 15 – Sep 29 |
Nearby cities in Texas
- Houston — zone 9b, last frost Feb 18, first frost Dec 8
- Sugar Land — zone 9b, last frost Feb 20, first frost Dec 3
- Pasadena — zone 9b, last frost Feb 10, first frost Dec 10
- Baytown — zone 9b, last frost Mar 2, first frost Nov 25
- Missouri City — zone 9b, last frost Mar 1, first frost Nov 27
- Pearland — zone 9b, last frost Feb 15, first frost Dec 10
More: all Texas cities · other zone 9a cities: San Antonio, TX, Austin, TX, Seattle, WA, Las Vegas, NV, Portland, OR, Tucson, AZ, Baton Rouge, LA, Tallahassee, FL
Conroe gardening questions
When is the last frost in Conroe, TX?
Plan around Mar 4. At NOAA's Conroe, TX station, 0.1 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 Feb 24, and after Mar 17 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Feb 2. Springs here are erratic: 50 days separate the 90% and 10% dates, versus a median of 36 days for cities on this site, so watch the forecast rather than the calendar.
When should I plant tomatoes in Conroe, TX?
Start seeds indoors Jan 7 – Jan 21 and set transplants outside Mar 11 – Mar 25, once nights stay above 50°F and the soil is near 60°F. With about 265 frost-free days, frost is not the main limit — fruit set drops when nights stay above about 75°F, so early plantings tend to do best. More: tomato planting dates by zone.
How long is the growing season in Conroe?
About 285 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 253 days, and in 1 year in 10 it runs 324 days or more. In fall there is a 10% chance of frost by Nov 11 and a 30% chance by Nov 24. That ranks 17th longest of 55 Texas cities on this site.
When should I plant a fall garden in Conroe?
Count back from the first fall frost (Nov 24): transplant broccoli Sep 1 – Sep 15; sow kale Sep 15 – Oct 13; sow lettuce Sep 15 – Oct 13; sow radishes Oct 13 – Nov 10. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Dec 23. How the math works: succession and fall planting.
Did Conroe's hardiness zone change on the 2023 map?
Yes. Most of Conroe was zone 8b on the 2012 map and is zone 9a 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 Conroe compare with Houston, TX?
Conroe is zone 9a and Houston is zone 9b. The typical last spring frost in Conroe (Mar 4) comes about 14 days later than in Houston, TX (Feb 18), 38 miles away, and the first fall frost is Nov 24 versus Dec 8. Conroe sits about 175 ft higher, which explains part of the gap. The two cities use different NOAA stations.