New Castle, PA planting zone & frost dates
New Castle is in USDA hardiness zone 6b. The last spring frost usually comes around April 30 and the first fall frost around October 23, for a growing season of about 175 days.
Planting calendar for New Castle
Dates are counted from the average last spring frost (April 30) 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: Mar 5 – Mar 19 Transplant outdoors: May 7 – May 14 |
| Peppers | Start seeds indoors: Feb 19 – Mar 5 Transplant outdoors: May 14 – May 21 |
| Eggplant | Start seeds indoors: Feb 19 – Mar 5 Transplant outdoors: May 14 – May 21 |
| Broccoli | Start seeds indoors: Feb 19 – Mar 5 Transplant outdoors: Apr 2 – Apr 16 |
| Cabbage | Start seeds indoors: Feb 19 – Mar 5 Transplant outdoors: Apr 2 – Apr 16 |
| Onions (sets) | Plant outdoors: Apr 2 – Apr 16 |
| Peas | Sow outdoors: Mar 19 – Apr 2 |
| Spinach | Sow outdoors: Mar 19 – Apr 2 |
| Lettuce | Sow outdoors: Apr 2 – Apr 16 |
| Carrots | Sow outdoors: Apr 2 – Apr 16 |
| Potatoes | Plant outdoors: Apr 2 – Apr 16 |
| Beans | Sow outdoors: May 7 – May 14 |
| Sweet corn | Sow outdoors: May 7 – May 14 |
| Cucumbers | Sow outdoors: May 7 – May 14 |
| Squash & zucchini | Sow outdoors: May 7 – May 14 |
| Basil | Start seeds indoors: Mar 19 – Apr 2 Transplant outdoors: May 7 – May 14 |
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 | Apr 17 | Apr 30 | May 19 |
| First 32°F frost in fall is before | Nov 4 | Oct 23 | Oct 6 |
How to read it: in spring there is a 10% chance of a frost after May 19, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 6. A hard freeze (28°F) usually ends around April 20.
Hardiness zone by ZIP code in New Castle
- 16101 zone 6a
- 16102 zone 6a
- 16103 zone 6b
- 16105 zone 6a
- 16107 zone 6a
- 16108 zone 6a
Nearby cities
- Hermitage zone 6a, last frost May 15
- Sharon zone 6a, last frost May 1
- Fernway zone 6b, last frost Apr 27
- Cranberry Township zone 6b, last frost Apr 8
- Butler zone 6b, last frost May 7
- Franklin Park zone 6b, last frost Apr 24
- Carnot-Moon zone 6b, last frost Apr 28
- Allison Park zone 6b, last frost Apr 16
Questions
What growing zone is New Castle, PA?
New Castle is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 6a.
When is the last frost in New Castle?
The average last spring frost (32°F) in New Castle is April 30. There is still a 10% chance of frost until May 19.
When can I plant tomatoes in New Castle?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 7 – May 14. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station New Castle 1 N, PA (USC00366233), 1.9 km (1.2 mi) from the city center, elevation 252 m, based on 27 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.