GreenlyPhiladelphia: frost dates
United States
In Philadelphia the last spring frost usually comes around 3 April and the first autumn frost around 11 November, which leaves about 222 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 29 April.
| Last spring frost | around 3 April |
|---|---|
| First autumn frost | around 11 November |
| Frost-free days | 222 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Achocha | 8 February | 20 March | 10 April |
| Arugula | — | 20 February | sow 13 March |
| Basil | 16 March | 23 April | 14 May |
| Beet | — | 20 February | sow 13 March |
| Bell Pepper | 8 February | 23 April | 14 May |
| Black-eyed Susan | 7 February | — | 10 April |
| Bok Choy | 13 February | 20 March | 10 April |
| Broad bean | — | 20 February | sow 13 March |
| Broccoli | — | 20 February | sow 13 March |
| Brussels Sprouts | 6 January | 20 February | 13 March |
| Cabbage | — | 20 February | sow 13 March |
| Calendula | — | 20 February | sow 13 March |
| Carrot | — | — | sow 13 March |
| Cauliflower | 9 January | 20 February | 13 March |
| Celeriac | 2 January | 20 March | 10 April |
| Celery | 2 January | 20 March | 10 April |
| Celosia | 26 February | 12 April | 3 May |
| Chamomile | — | 20 February | sow 13 March |
| Chayote | 24 December | 22 March | 12 April |
| Chickpea | — | — | sow 13 March |
| Chili Pepper | 25 February | 10 May | 31 May |
| China aster | 2 March | 23 April | 14 May |
| Chives | — | — | sow 13 March |
| Cilantro | — | 20 February | sow 13 March |
| Corn | — | 22 March | sow 12 April |
| Cosmos | 26 February | 12 April | 3 May |
| Cucumber | 12 March | 23 April | 14 May |
| Daikon | — | 20 February | sow 13 March |
| Delphinium | 13 January | — | 13 March |
| Dill | — | 20 February | sow 13 March |
| Eggplant | 12 February | 23 April | 14 May |
| Florence fennel | 3 February | 20 March | 10 April |
| Garden sorrel | — | 20 February | sow 13 March |
| Green Beans | 13 February | 22 March | 12 April |
| Hyssop | — | — | sow 13 March |
| Kale | — | 20 February | sow 13 March |
| Kiwano | 7 March | 8 April | 29 April |
| Kohlrabi | — | 20 February | sow 13 March |
| Leek | 12 December | 20 February | 13 March |
| Lemon balm | — | 20 February | sow 13 March |
| Lettuce | — | 20 February | sow 13 March |
| Lisianthus | 25 November | 20 February | 13 March |
| Lovage | — | — | sow 13 March |
| Luffa | 12 March | 23 April | 14 May |
| Marigold | 6 February | 20 March | 10 April |
| Melon | 2 March | 23 April | 14 May |
| Microgreens | — | 12 April | sow 3 May |
| Moringa | 16 March | 10 May | 31 May |
| Mustard greens | — | 20 February | sow 13 March |
| Napa cabbage | 15 February | 20 March | 10 April |
| Nasturtium | 10 February | 20 March | 10 April |
| Okra | 12 March | 23 April | 14 May |
| Oregano | 22 December | 20 February | 13 March |
| Pansy | 26 December | 20 February | 13 March |
| Parsley | — | 20 February | sow 13 March |
| Parsnip | — | — | sow 13 March |
| Peanut | 17 March | 23 April | 14 May |
| Peas | — | 20 February | sow 13 March |
| Petunia | 19 February | 23 April | 14 May |
| Physalis | 22 February | 8 April | 29 April |
| Pumpkin | 2 March | 8 April | 29 April |
| Purple coneflower | 10 January | — | 13 March |
| Radish | — | — | sow 13 March |
| Sage | 2 January | 20 February | 13 March |
| Snapdragon | 17 December | 20 February | 13 March |
| Spinach | — | 20 February | sow 13 March |
| Stevia | 18 February | 8 April | 29 April |
| Stock | — | 20 February | sow 13 March |
| Sunflower | — | 12 April | sow 3 May |
| Sweet Corn | — | 22 March | sow 12 April |
| Sweet pea | 9 January | 20 February | 13 March |
| Sweet William | — | — | sow 13 March |
| Swiss Chard | — | 20 February | sow 13 March |
| Thyme | — | 20 February | sow 13 March |
| Tomato | 10 February | 8 April | 29 April |
| Turnip | — | 20 February | sow 13 March |
| Watercress | — | 20 February | sow 13 March |
| Watermelon | 22 March | 23 April | 14 May |
| Zinnia | 5 April | 10 May | 31 May |
| Zucchini | 7 March | 8 April | 29 April |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.
Philadelphia: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Planted in autumn
| Crop | Plant around |
|---|---|
| Bearded Iris | 12 October |
| Crocus | 12 October |
| Daffodil | 12 October |
| Garlic | 12 October |
| Hyacinth | 12 October |
| Lily | 12 October |
| Peony | 12 October |
| Saffron | 12 October |
| Tulip | 12 October |
| Wild garlic | 12 October |
A month before the first autumn frost, so the roots grow before winter.