Harrisburg, PA planting zone & frost dates
Harrisburg is in USDA hardiness zone 7a. The last spring frost usually comes around April 15 and the first fall frost around October 23, for a growing season of about 189 days.
Planting calendar for Harrisburg
Dates are counted from the average last spring frost (April 15) 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 18 – Mar 4 Transplant outdoors: Apr 22 – Apr 29 |
| Peppers | Start seeds indoors: Feb 4 – Feb 18 Transplant outdoors: Apr 29 – May 6 |
| Eggplant | Start seeds indoors: Feb 4 – Feb 18 Transplant outdoors: Apr 29 – May 6 |
| Broccoli | Start seeds indoors: Feb 4 – Feb 18 Transplant outdoors: Mar 18 – Apr 1 |
| Cabbage | Start seeds indoors: Feb 4 – Feb 18 Transplant outdoors: Mar 18 – Apr 1 |
| Onions (sets) | Plant outdoors: Mar 18 – Apr 1 |
| Peas | Sow outdoors: Mar 4 – Mar 18 |
| Spinach | Sow outdoors: Mar 4 – Mar 18 |
| Lettuce | Sow outdoors: Mar 18 – Apr 1 |
| Carrots | Sow outdoors: Mar 18 – Apr 1 |
| Potatoes | Plant outdoors: Mar 18 – Apr 1 |
| Beans | Sow outdoors: Apr 22 – Apr 29 |
| Sweet corn | Sow outdoors: Apr 22 – Apr 29 |
| Cucumbers | Sow outdoors: Apr 22 – Apr 29 |
| Squash & zucchini | Sow outdoors: Apr 22 – Apr 29 |
| Basil | Start seeds indoors: Mar 4 – Mar 18 Transplant outdoors: Apr 22 – Apr 29 |
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 7a 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
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Apr 1 | Apr 15 | May 2 |
| First 32°F frost in fall is before | Nov 7 | Oct 23 | Oct 7 |
How to read it: in spring there is a 10% chance of a frost after May 2, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 7. A hard freeze (28°F) usually ends around April 3.
Hardiness zone by ZIP code in Harrisburg
- 17101 zone 7a
- 17102 zone 7a
- 17103 zone 7a
- 17104 zone 7a
- 17105 zone 7a
- 17106 zone 7a
- 17107 zone 7a
- 17108 zone 7a
- 17109 zone 7a
- 17110 zone 7a
- 17111 zone 7a
- 17112 zone 7a
- 17113 zone 7a
- 17120 zone 7a
- 17121 zone 7a
- 17122 zone 7a
- 17123 zone 7a
- 17124 zone 7a
- 17125 zone 7a
- 17126 zone 7a
- 17127 zone 7a
- 17128 zone 7a
- 17129 zone 7a
- 17130 zone 7a
- 17140 zone 7a
- 17177 zone 7a
Nearby cities
- Colonial Park zone 7a, last frost Apr 15
- Hershey zone 7a, last frost Apr 9
- Weigelstown zone 7a, last frost Apr 27
- Elizabethtown zone 7a, last frost Apr 9
- Shiloh zone 7a, last frost Apr 26
- Carlisle zone 7a, last frost Apr 23
- York zone 7a, last frost Apr 26
- Columbia zone 7a, last frost Apr 30
Questions
What growing zone is Harrisburg, PA?
Harrisburg 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 Harrisburg?
The average last spring frost (32°F) in Harrisburg is April 15. There is still a 10% chance of frost until May 2.
When can I plant tomatoes in Harrisburg?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 22 – Apr 29. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Harrisburg 1 Ne, PA (USC00363698), 1.5 km (0.9 mi) from the city center, elevation 128 m, based on 22 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.