Troy, MO planting zone & frost dates
Troy is in USDA hardiness zone 6b. The last spring frost usually comes around April 14 and the first fall frost around October 23, for a growing season of about 191 days.
Planting calendar for Troy
Dates are counted from the average last spring frost (April 14) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 17 – Mar 3 Transplant outdoors: Apr 21 – Apr 28 |
| Peppers | Start seeds indoors: Feb 3 – Feb 17 Transplant outdoors: Apr 28 – May 5 |
| Eggplant | Start seeds indoors: Feb 3 – Feb 17 Transplant outdoors: Apr 28 – May 5 |
| Broccoli | Start seeds indoors: Feb 3 – Feb 17 Transplant outdoors: Mar 17 – Mar 31 |
| Cabbage | Start seeds indoors: Feb 3 – Feb 17 Transplant outdoors: Mar 17 – Mar 31 |
| Onions (sets) | Plant outdoors: Mar 17 – Mar 31 |
| Peas | Sow outdoors: Mar 3 – Mar 17 |
| Spinach | Sow outdoors: Mar 3 – Mar 17 |
| Lettuce | Sow outdoors: Mar 17 – Mar 31 |
| Carrots | Sow outdoors: Mar 17 – Mar 31 |
| Potatoes | Plant outdoors: Mar 17 – Mar 31 |
| Beans | Sow outdoors: Apr 21 – Apr 28 |
| Sweet corn | Sow outdoors: Apr 21 – Apr 28 |
| Cucumbers | Sow outdoors: Apr 21 – Apr 28 |
| Squash & zucchini | Sow outdoors: Apr 21 – Apr 28 |
| Basil | Start seeds indoors: Mar 3 – Mar 17 Transplant outdoors: Apr 21 – Apr 28 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 28 (8 weeks before the average first fall frost on Oct 23).
Useful for zone 6b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Mar 31 | Apr 14 | May 3 |
| First 32°F frost in fall is before | Nov 5 | Oct 23 | Oct 9 |
How to read it: in spring there is a 10% chance of a frost after May 3, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 9. A hard freeze (28°F) usually ends around April 3.
Hardiness zone by ZIP code in Troy
- 63379 zone 6b
Nearby cities
- Wentzville zone 6b, last frost Apr 10
- Lake Saint Louis zone 6b, last frost Apr 10
- O'Fallon zone 6b, last frost Apr 9
- Dardenne Prairie zone 6b, last frost Apr 10
- Saint Peters zone 6b, last frost Apr 9
- Washington zone 6b, last frost Apr 8
- Wildwood zone 7a, last frost Apr 12
- Chesterfield zone 7a, last frost Apr 4
Questions
What growing zone is Troy, MO?
Troy is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map.
When is the last frost in Troy?
The average last spring frost (32°F) in Troy is April 14. There is still a 10% chance of frost until May 3.
When can I plant tomatoes in Troy?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 21 – Apr 28. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Warrenton 1 N, MO (USC00238725), 21.1 km (13.1 mi) from the city center, elevation 252 m, based on 24 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.