Mount Lebanon, PA planting zone & frost dates
Mount Lebanon is in USDA hardiness zone 6b. The last spring frost usually comes around April 18 and the first fall frost around October 28, for a growing season of about 193 days.
Planting calendar for Mount Lebanon
Dates are counted from the average last spring frost (April 18) 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 21 – Mar 7 Transplant outdoors: Apr 25 – May 2 |
| Peppers | Start seeds indoors: Feb 7 – Feb 21 Transplant outdoors: May 2 – May 9 |
| Eggplant | Start seeds indoors: Feb 7 – Feb 21 Transplant outdoors: May 2 – May 9 |
| Broccoli | Start seeds indoors: Feb 7 – Feb 21 Transplant outdoors: Mar 21 – Apr 4 |
| Cabbage | Start seeds indoors: Feb 7 – Feb 21 Transplant outdoors: Mar 21 – Apr 4 |
| Onions (sets) | Plant outdoors: Mar 21 – Apr 4 |
| Peas | Sow outdoors: Mar 7 – Mar 21 |
| Spinach | Sow outdoors: Mar 7 – Mar 21 |
| Lettuce | Sow outdoors: Mar 21 – Apr 4 |
| Carrots | Sow outdoors: Mar 21 – Apr 4 |
| Potatoes | Plant outdoors: Mar 21 – Apr 4 |
| Beans | Sow outdoors: Apr 25 – May 2 |
| Sweet corn | Sow outdoors: Apr 25 – May 2 |
| Cucumbers | Sow outdoors: Apr 25 – May 2 |
| Squash & zucchini | Sow outdoors: Apr 25 – May 2 |
| Basil | Start seeds indoors: Mar 7 – Mar 21 Transplant outdoors: Apr 25 – May 2 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 2 (8 weeks before the average first fall frost on Oct 28).
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 2 | Apr 18 | May 6 |
| First 32°F frost in fall is before | Nov 10 | Oct 28 | Oct 14 |
How to read it: in spring there is a 10% chance of a frost after May 6, 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 April 5.
Nearby cities
- Bethel Park zone 6b, last frost Apr 18
- Upper Saint Clair zone 6b, last frost Apr 18
- Whitehall zone 6b, last frost Apr 18
- Baldwin zone 6b, last frost Apr 18
- South Park Township zone 6b, last frost Apr 18
- Pittsburgh zone 6b, last frost Apr 24
- Jefferson Hills zone 6b, last frost Apr 18
- Munhall zone 6b, last frost Apr 5
Questions
What growing zone is Mount Lebanon, PA?
Mount Lebanon 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 Mount Lebanon?
The average last spring frost (32°F) in Mount Lebanon is April 18. There is still a 10% chance of frost until May 6.
When can I plant tomatoes in Mount Lebanon?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 25 – May 2. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Pittsburgh Allegheny Co Ap, PA (USW00014762), 10.8 km (6.7 mi) from the city center, elevation 380 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.