GreenlyWashington, D.C.: frost dates
United States
In Washington, D.C. the last spring frost usually comes around 31 March and the first autumn frost around 16 November, which leaves about 230 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 15 April.
| Last spring frost | around 31 March |
|---|---|
| First autumn frost | around 16 November |
| Frost-free days | 230 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 | 5 February | 17 March | 7 April |
| Arugula | — | 17 February | sow 10 March |
| Basil | 6 March | 13 April | 4 May |
| Beet | — | 17 February | sow 10 March |
| Bell Pepper | 29 January | 13 April | 4 May |
| Black-eyed Susan | 4 February | — | 7 April |
| Bok Choy | 10 February | 17 March | 7 April |
| Broad bean | — | 17 February | sow 10 March |
| Broccoli | — | 17 February | sow 10 March |
| Brussels Sprouts | 3 January | 17 February | 10 March |
| Cabbage | — | 17 February | sow 10 March |
| Calendula | — | 17 February | sow 10 March |
| Carrot | — | — | sow 10 March |
| Cauliflower | 6 January | 17 February | 10 March |
| Celeriac | 30 December | 17 March | 7 April |
| Celery | 30 December | 17 March | 7 April |
| Celosia | 16 February | 2 April | 23 April |
| Chamomile | — | 17 February | sow 10 March |
| Chayote | 19 December | 17 March | 7 April |
| Chickpea | — | — | sow 10 March |
| Chili Pepper | 17 February | 2 May | 23 May |
| China aster | 20 February | 13 April | 4 May |
| Chives | — | — | sow 10 March |
| Cilantro | — | 17 February | sow 10 March |
| Corn | — | 17 March | sow 7 April |
| Cosmos | 16 February | 2 April | 23 April |
| Cucumber | 2 March | 13 April | 4 May |
| Daikon | — | 17 February | sow 10 March |
| Delphinium | 10 January | — | 10 March |
| Dill | — | 17 February | sow 10 March |
| Eggplant | 2 February | 13 April | 4 May |
| Florence fennel | 31 January | 17 March | 7 April |
| Garden sorrel | — | 17 February | sow 10 March |
| Green Beans | 8 February | 17 March | 7 April |
| Hyssop | — | — | sow 10 March |
| Kale | — | 17 February | sow 10 March |
| Kiwano | 21 February | 25 March | 15 April |
| Kohlrabi | — | 17 February | sow 10 March |
| Leek | 9 December | 17 February | 10 March |
| Lemon balm | — | 17 February | sow 10 March |
| Lettuce | — | 17 February | sow 10 March |
| Lisianthus | 22 November | 17 February | 10 March |
| Lovage | — | — | sow 10 March |
| Luffa | 2 March | 13 April | 4 May |
| Marigold | 3 February | 17 March | 7 April |
| Melon | 20 February | 13 April | 4 May |
| Microgreens | — | 2 April | sow 23 April |
| Moringa | 8 March | 2 May | 23 May |
| Mustard greens | — | 17 February | sow 10 March |
| Napa cabbage | 12 February | 17 March | 7 April |
| Nasturtium | 7 February | 17 March | 7 April |
| Okra | 2 March | 13 April | 4 May |
| Oregano | 19 December | 17 February | 10 March |
| Pansy | 23 December | 17 February | 10 March |
| Parsley | — | 17 February | sow 10 March |
| Parsnip | — | — | sow 10 March |
| Peanut | 7 March | 13 April | 4 May |
| Peas | — | 17 February | sow 10 March |
| Petunia | 9 February | 13 April | 4 May |
| Physalis | 8 February | 25 March | 15 April |
| Pumpkin | 16 February | 25 March | 15 April |
| Purple coneflower | 7 January | — | 10 March |
| Radish | — | — | sow 10 March |
| Sage | 30 December | 17 February | 10 March |
| Snapdragon | 14 December | 17 February | 10 March |
| Spinach | — | 17 February | sow 10 March |
| Stevia | 4 February | 25 March | 15 April |
| Stock | — | 17 February | sow 10 March |
| Sunflower | — | 2 April | sow 23 April |
| Sweet Corn | — | 17 March | sow 7 April |
| Sweet pea | 6 January | 17 February | 10 March |
| Sweet William | — | — | sow 10 March |
| Swiss Chard | — | 17 February | sow 10 March |
| Thyme | — | 17 February | sow 10 March |
| Tomato | 27 January | 25 March | 15 April |
| Turnip | — | 17 February | sow 10 March |
| Watercress | — | 17 February | sow 10 March |
| Watermelon | 12 March | 13 April | 4 May |
| Zinnia | 28 March | 2 May | 23 May |
| Zucchini | 21 February | 25 March | 15 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.
Washington, D.C.: 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 | 17 October |
| Crocus | 17 October |
| Daffodil | 17 October |
| Garlic | 17 October |
| Hyacinth | 17 October |
| Lily | 17 October |
| Peony | 17 October |
| Saffron | 17 October |
| Tulip | 17 October |
| Wild garlic | 17 October |
A month before the first autumn frost, so the roots grow before winter.