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 |
|---|---|---|---|
| Bell Pepper | 21 February | 6 May | 27 May |
| Chili Pepper | 25 February | 10 May | 31 May |
| Corn | — | 10 April | sow 1 May |
| Cucumber | 25 March | 6 May | 27 May |
| Eggplant | 25 February | 6 May | 27 May |
| Green Beans | 4 March | 10 April | 1 May |
| Melon | 15 March | 6 May | 27 May |
| Peas | — | 13 March | sow 3 April |
| Physalis | 9 March | 23 April | 14 May |
| Pumpkin | 17 March | 23 April | 14 May |
| Sweet Corn | — | 10 April | sow 1 May |
| Tomato | 25 February | 23 April | 14 May |
| Watermelon | 4 April | 6 May | 27 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 |
|---|---|
| Crocus | 8 October |
| Daffodil | 8 October |
| Garlic | 8 October |
| Hyacinth | 8 October |
| Lily | 8 October |
| Tulip | 8 October |
A month before the first autumn frost, so the roots grow before winter.