Butler, PA planting zone & frost dates
Butler is in USDA hardiness zone 6b. The last spring frost usually comes around May 7 and the first fall frost around October 14, for a growing season of about 159 days.
Planting calendar for Butler
Dates are counted from the average last spring frost (May 7) 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 12 – Mar 26 Transplant outdoors: May 14 – May 21 |
| Peppers | Start seeds indoors: Feb 26 – Mar 12 Transplant outdoors: May 21 – May 28 |
| Eggplant | Start seeds indoors: Feb 26 – Mar 12 Transplant outdoors: May 21 – May 28 |
| Broccoli | Start seeds indoors: Feb 26 – Mar 12 Transplant outdoors: Apr 9 – Apr 23 |
| Cabbage | Start seeds indoors: Feb 26 – Mar 12 Transplant outdoors: Apr 9 – Apr 23 |
| Onions (sets) | Plant outdoors: Apr 9 – Apr 23 |
| Peas | Sow outdoors: Mar 26 – Apr 9 |
| Spinach | Sow outdoors: Mar 26 – Apr 9 |
| Lettuce | Sow outdoors: Apr 9 – Apr 23 |
| Carrots | Sow outdoors: Apr 9 – Apr 23 |
| Potatoes | Plant outdoors: Apr 9 – Apr 23 |
| Beans | Sow outdoors: May 14 – May 21 |
| Sweet corn | Sow outdoors: May 14 – May 21 |
| Cucumbers | Sow outdoors: May 14 – May 21 |
| Squash & zucchini | Sow outdoors: May 14 – May 21 |
| Basil | Start seeds indoors: Mar 26 – Apr 9 Transplant outdoors: May 14 – May 21 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Aug 19 (8 weeks before the average first fall frost on Oct 14).
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 22 | May 7 | May 23 |
| First 32°F frost in fall is before | Oct 30 | Oct 14 | Oct 1 |
How to read it: in spring there is a 10% chance of a frost after May 23, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 1. A hard freeze (28°F) usually ends around April 26.
Hardiness zone by ZIP code in Butler
- 16001 zone 6a
- 16002 zone 6a
- 16003 zone 6b
Nearby cities
- Cranberry Township zone 6b, last frost Apr 8
- Fernway zone 6b, last frost Apr 27
- Natrona Heights zone 6b, last frost Apr 16
- Allison Park zone 6b, last frost Apr 16
- New Kensington zone 6b, last frost Apr 16
- Lower Burrell zone 6b, last frost Apr 16
- Franklin Park zone 6b, last frost Apr 24
- Plum zone 6b, last frost Apr 16
Questions
What growing zone is Butler, PA?
Butler 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 Butler?
The average last spring frost (32°F) in Butler is May 7. There is still a 10% chance of frost until May 23.
When can I plant tomatoes in Butler?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around May 14 – May 21. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Butler 2 Sw, PA (USC00361139), 2.8 km (1.7 mi) from the city center, elevation 305 m, based on 26 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.