GreenlyDetroit: frost dates
United States
In Detroit the last spring frost usually comes around 24 April and the first autumn frost around 7 November, which leaves about 197 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 14 May.
| Last spring frost | around 24 April |
|---|---|
| First autumn frost | around 7 November |
| Frost-free days | 197 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 | 1 March | 10 April | 1 May |
| Arugula | — | 13 March | sow 3 April |
| Basil | 29 March | 6 May | 27 May |
| Beet | — | 13 March | sow 3 April |
| Bell Pepper | 21 February | 6 May | 27 May |
| Black-eyed Susan | 28 February | — | 1 May |
| Bok Choy | 6 March | 10 April | 1 May |
| Broad bean | — | 13 March | sow 3 April |
| Broccoli | — | 13 March | sow 3 April |
| Brussels Sprouts | 27 January | 13 March | 3 April |
| Cabbage | — | 13 March | sow 3 April |
| Calendula | — | 13 March | sow 3 April |
| Carrot | — | — | sow 3 April |
| Cauliflower | 30 January | 13 March | 3 April |
| Celeriac | 23 January | 10 April | 1 May |
| Celery | 23 January | 10 April | 1 May |
| Celosia | 12 March | 26 April | 17 May |
| Chamomile | — | 13 March | sow 3 April |
| Chayote | 12 January | 10 April | 1 May |
| Chickpea | — | — | sow 3 April |
| Chili Pepper | 25 February | 10 May | 31 May |
| China aster | 15 March | 6 May | 27 May |
| Chives | — | — | sow 3 April |
| Cilantro | — | 13 March | sow 3 April |
| Corn | — | 10 April | sow 1 May |
| Cosmos | 12 March | 26 April | 17 May |
| Cucumber | 25 March | 6 May | 27 May |
| Daikon | — | 13 March | sow 3 April |
| Delphinium | 3 February | — | 3 April |
| Dill | — | 13 March | sow 3 April |
| Eggplant | 25 February | 6 May | 27 May |
| Florence fennel | 24 February | 10 April | 1 May |
| Garden sorrel | — | 13 March | sow 3 April |
| Green Beans | 4 March | 10 April | 1 May |
| Hyssop | — | — | sow 3 April |
| Kale | — | 13 March | sow 3 April |
| Kiwano | 22 March | 23 April | 14 May |
| Kohlrabi | — | 13 March | sow 3 April |
| Leek | 2 January | 13 March | 3 April |
| Lemon balm | — | 13 March | sow 3 April |
| Lettuce | — | 13 March | sow 3 April |
| Lisianthus | 16 December | 13 March | 3 April |
| Lovage | — | — | sow 3 April |
| Luffa | 25 March | 6 May | 27 May |
| Marigold | 27 February | 10 April | 1 May |
| Melon | 15 March | 6 May | 27 May |
| Microgreens | — | 26 April | sow 17 May |
| Moringa | 16 March | 10 May | 31 May |
| Mustard greens | — | 13 March | sow 3 April |
| Napa cabbage | 8 March | 10 April | 1 May |
| Nasturtium | 3 March | 10 April | 1 May |
| Okra | 25 March | 6 May | 27 May |
| Oregano | 12 January | 13 March | 3 April |
| Pansy | 16 January | 13 March | 3 April |
| Parsley | — | 13 March | sow 3 April |
| Parsnip | — | — | sow 3 April |
| Peanut | 30 March | 6 May | 27 May |
| Peas | — | 13 March | sow 3 April |
| Petunia | 4 March | 6 May | 27 May |
| Physalis | 9 March | 23 April | 14 May |
| Pumpkin | 17 March | 23 April | 14 May |
| Purple coneflower | 31 January | — | 3 April |
| Radish | — | — | sow 3 April |
| Sage | 23 January | 13 March | 3 April |
| Snapdragon | 7 January | 13 March | 3 April |
| Spinach | — | 13 March | sow 3 April |
| Stevia | 5 March | 23 April | 14 May |
| Stock | — | 13 March | sow 3 April |
| Sunflower | — | 26 April | sow 17 May |
| Sweet Corn | — | 10 April | sow 1 May |
| Sweet pea | 30 January | 13 March | 3 April |
| Sweet William | — | — | sow 3 April |
| Swiss Chard | — | 13 March | sow 3 April |
| Thyme | — | 13 March | sow 3 April |
| Tomato | 25 February | 23 April | 14 May |
| Turnip | — | 13 March | sow 3 April |
| Watercress | — | 13 March | sow 3 April |
| Watermelon | 4 April | 6 May | 27 May |
| Zinnia | 5 April | 10 May | 31 May |
| Zucchini | 22 March | 23 April | 14 May |
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.
Detroit: 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 | 8 October |
| Crocus | 8 October |
| Daffodil | 8 October |
| Garlic | 8 October |
| Hyacinth | 8 October |
| Lily | 8 October |
| Peony | 8 October |
| Saffron | 8 October |
| Tulip | 8 October |
| Wild garlic | 8 October |
A month before the first autumn frost, so the roots grow before winter.