Arnold, MO planting zone & frost dates
Arnold is in USDA hardiness zone 7a. The last spring frost usually comes around April 6 and the first fall frost around October 27, for a growing season of about 203 days.
Planting calendar for Arnold
Dates are counted from the average last spring frost (April 6) 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 9 – Feb 23 Transplant outdoors: Apr 13 – Apr 20 |
| Peppers | Start seeds indoors: Jan 26 – Feb 9 Transplant outdoors: Apr 20 – Apr 27 |
| Eggplant | Start seeds indoors: Jan 26 – Feb 9 Transplant outdoors: Apr 20 – Apr 27 |
| Broccoli | Start seeds indoors: Jan 26 – Feb 9 Transplant outdoors: Mar 9 – Mar 23 |
| Cabbage | Start seeds indoors: Jan 26 – Feb 9 Transplant outdoors: Mar 9 – Mar 23 |
| Onions (sets) | Plant outdoors: Mar 9 – Mar 23 |
| Peas | Sow outdoors: Feb 23 – Mar 9 |
| Spinach | Sow outdoors: Feb 23 – Mar 9 |
| Lettuce | Sow outdoors: Mar 9 – Mar 23 |
| Carrots | Sow outdoors: Mar 9 – Mar 23 |
| Potatoes | Plant outdoors: Mar 9 – Mar 23 |
| Beans | Sow outdoors: Apr 13 – Apr 20 |
| Sweet corn | Sow outdoors: Apr 13 – Apr 20 |
| Cucumbers | Sow outdoors: Apr 13 – Apr 20 |
| Squash & zucchini | Sow outdoors: Apr 13 – Apr 20 |
| Basil | Start seeds indoors: Feb 23 – Mar 9 Transplant outdoors: Apr 13 – Apr 20 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 1 (8 weeks before the average first fall frost on Oct 27).
Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Mar 22 | Apr 6 | Apr 20 |
| First 32°F frost in fall is before | Nov 7 | Oct 27 | Oct 14 |
How to read it: in spring there is a 10% chance of a frost after April 20, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 14. A hard freeze (28°F) usually ends around March 27.
Hardiness zone by ZIP code in Arnold
- 63010 zone 7a
Nearby cities
Questions
What growing zone is Arnold, MO?
Arnold is in USDA Plant Hardiness Zone 7a (average extreme winter low 0°F to 5°F), according to the USDA 2023 map.
When is the last frost in Arnold?
The average last spring frost (32°F) in Arnold is April 6. There is still a 10% chance of frost until April 20.
When can I plant tomatoes in Arnold?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 13 – Apr 20. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Cahokia, IL (USC00111160), 21.8 km (13.5 mi) from the city center, elevation 122 m, based on 20 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.